Space Plasma Physics

About PPPL Established in 1951, the Princeton Plasma Physics Laboratory (PPPL) is dedicated to developing the scientifi c and technological knowledge base for fusion energy as a safe, econom- ical, and environmentally attractive energy source for the world’s long-term energy requirements. It was the site of the Tokamak Fusion Test Reactor which completed a historic series of experiments using deuterium-tritium fuel in April 1997. A new innovative facility, the National Spherical Torus Experiment, came into operation in 1999, ahead of schedule and on budget. Princeton University manages PPPL under contract with the U.S. Department of Energy. The fi scal year 2003 budget was approximately $66.5 million. The number of full-time regular employees at the end of the fi scal year was 420, not including approximately 30 subcontractors and limited duration employees, 35 graduate students, and visiting research staff. The Laboratory is sited on 88 acres of Princeton University’s James Forrestal Campus, about four miles from the main campus. Through its efforts to build and operate magnetic fusion devices, PPPL has gained extensive capabilities in a host of disciplines including advanced computational simulations, vacuum technology, mechanics, materials science, electronics, computer technology, and high-voltage power systems. In addition, PPPL scientists and engineers are applying knowledge gained in fusion research to other theoretical and experimental areas including the development of plasma thrusters and propagation of intense beams of ions. The Laboratory’s Offi ce of Technolo- gy Transfer assists industry, other universities, and state and local government in transferring these technologies to the commercial sector. The Laboratory’s graduate education and science education programs provide educational opportunities for students and teachers from elementary school through postgraduate studies.

On The Cover A new experimental device, the National Compact Stellarator Experiment (NCSX), is being constructed at the Princeton Plasma Physics Laboratory in partnership with the Oak Ridge National Laboratory. NCSX is the centerpiece of a national program to develop the compact- stellarator plasma-confi nement concept. During fi scal year 2003, the NCSX fabrication project offi cially started. Good progress on its design permitted the project to advance from conceptual design to a level of maturity suffi cient to establish the cost and schedule baseline for project execution. A computer-generated cutaway rendition of NCSX is shown with individual key components. From the upper left are: one fi eld-period subassembly, a modular coil subassembly, a toroidal-fi eld coil subassembly, the modular coil assembly, an NCSX plasma and the modular coils, and the NCSX vacuum vessel assembly with thermal insulation.

This publication highlights activities at the Princeton Plasma Physics Laboratory for ﬁ scal year 2003 — 1 October 2002 through 30 September 2003. Mission The U.S. Department of Energy’s Princeton Plasma Physics Laboratory is a Collaborative National Center for plasma and fusion science. Its primary mission is to develop the scientiﬁ c understanding and the key innovations which will lead to an attractive energy source.

Associated missions include conducting world-class research along the broad frontier of plasma science and technology, and providing the highest quality of scientiﬁ c education.

Vision Deepening the understanding of plasmas and creating key innovations to make fusion power a practical reality.

i ii Advantages of Fusion Energy

• Worldwide availability of inexhaustible low-cost fuel. • No chemical combustion products and therefore no contribution to acid rain or global warming. • No runaway reaction possible. • Materials and by-products unsuitable for weapons production. • Radiological hazards thousands of times less than from ﬁ ssion.

iii iv Table of Contents

From the Director ...... vii Research National Spherical Torus Experiment ...... 1 Current Drive Experiment-Upgrade ...... 15 Magnetic Reconnection Experiment ...... 23 Theory and Advanced Simulations ...... 31 Computational Plasma Physics ...... 47 Off-site Research ...... 57 Doublet-III-D Collaborations ...... 57 Alcator C-Mod Collaborations ...... 61 International Collaborations ...... 67 Space Plasma Physics ...... 73 Basic and Applied Physics Experiments ...... 81 Hall Thruster Experiment ...... 81 Magnetic Nozzle Experiment ...... 83 FRC/RMF Experiment ...... 85 Nonneutral Plasmas and High-intensity Accelerators ...... 86 Diagnostic Development ...... 91 Liquid Metal Experiment ...... 94 Advanced Fusion Devices and Studies National Compact Stellarator Experiment ...... 97 Fusion Ignition Research Experiment ...... 105 Engineering and Technical Infrastructure ...... 113 Environment, Safety, and Health ...... 125 Applied Research and Technology Transfer ...... 127 Patents and Invention Disclosures ...... 137 Education Graduate Education ...... 139 Science Education ...... 143 Awards and Honors ...... 149 The Year in Pictures ...... 153 Financial Summary ...... 157 Organization and Stafﬁ ng ...... 159 PPPL Advisory Council ...... 161 Publications ...... 163 Abbreviations, Acronyms, and Symbols ...... 201

v vi From the Director

n January 30, 2003, President Bush announced “that the Unit- Oed States will join ITER, an ambitious international research project to harness the promise of fusion energy. The results of ITER will advance the effort to produce clean, safe, renewable, and com- mercially available fusion energy by the middle of this century. Commercialization of fusion has the potential to dramatical- ly improve America’s energy security while signifi cantly reducing air pollution and emissions of greenhouse gases.” Robert J. Goldston On the same day, Secretary of Ener- gy Spencer Abraham visited the Princeton perimental results from PPPL collaboration Plasma Physics Laboratory (PPPL) and at the W7-AS stellarator in Germany con- stated, “By the time our young children tinue to indicate that this will be a very ex- reach middle age, fusion may begin to de- citing experiment. The remarkable steadi- liver energy independence… and energy ness of stellarator plasmas in W7-AS, even abundance… to all nations rich and poor. at high beta, is very impressive. Fusion is a promise for the future we must Despite loss of eight experimental run- not ignore. But let me be clear, our decision weeks on the National Spherical Torus to join ITER in no way means a lesser role Experiment (NSTX), due to a coil joint for the fusion programs we undertake here failure, very good progress was made on at home. It is imperative that we maintain bringing new capabilities on line, includ- and enhance our strong domestic research ing an extremely high-resolution instru- program — at Princeton, at the universi- ment for measuring plasma ion temper- ties and at our other labs. Critical science ature and toroidal rotation, which will needs to be done in the U.S., in parallel allow unprecedented detail in determining with ITER, to strengthen our competitive the effects of magnetic structures on ro- position in fusion technology.” tating plasmas — and vice versa. Thermal With this degree of support at the high- confi nement and fast-ion data also pro- est levels in the Administration, FY03 was vided new insight into the physics of the a heady year for fusion research. At PPPL spherical torus confi guration. The NSTX we continued to make important advanc- underwent a very successful fi ve-year plan es in both the experimental and theoretical review, outlining the NSTX scientifi c pro- research needed to create the future envi- gram, including both research goals and sioned by our leaders. new facility capabilities that are needed to The National Compact Stellarator Ex- accomplish them. periment passed three closely spaced major Our off-site experimental research con- reviews, preparing it for the cost and sched- tinued to make important advances. On ule baseline of Critical Decision Two, ear- DIII-D at General Atomics in California, ly in F04. Theoretical analyses and new ex- we found the fi rst indications of direct vii feedback control of Resistive Wall Modes advance was achieved: a defi nitive set of and, on Alcator C-MOD at the Massa- hybrid fl uid-kinetic calculations explains chusetts Institute of Technology, the Gas the dynamics of the Field-reversed Con- Puff Imaging technique that is also being fi guration at large gyro-radius, including applied to NSTX revealed new physics in both the anomalous stabilization of the n the scrape-off layer. We have developed = 1 tilt mode and the consequent desta- new understanding of fast-ion instabilities bilization of the rotational m = 2 mode, on the Joint European Torus (JET), and just as seen in experiments. we have new diagnostic systems in prep- Continuing efforts to apply the latest aration for JET’s next deuterium-tritium computational techniques to fusion sim- phase of operations, to follow on from our ulations have paid off, for example with own deuterium-tritium experience on the the application of Adaptive Mesh Refi ne- Tokamak Fusion Test Reactor. ment techniques to the large M3D code. A On PPPL’s smaller experiments, we substantial computer cluster was brought have also made rapid progress. The Cur- on line to test the cluster approach to pro- rent Drive Experiment-Upgrade facility viding the fusion community with capac- has shown very positive results from the ity computing. It has supported nonlinear use of a liquid lithium limiter, and will be turbulence calculations in strong support modifi ed now to test this approach more of our off-site research efforts. We have extensively as the Lithium Tokamak Ex- also made the mature PPPL TRANSP periment. The Magnetic Reconnection data analysis code available to the interna- Experiment has had a breakthrough year. tional magnetic fusion research communi- For the fi rst time ever, anywhere, turbu- ty, through the Fusion Collaboratory. Of lence has been identifi ed which may ex- 1,662 TRANSP code runs accomplished plain the source of the anomalous resistivi- at PPPL in FY03, 717 were in support of ty that allows rapid magnetic reconnection NSTX and the rest supported experiments both in the laboratory and in space. The around the world. The Collaboratory en- Paul Trap Simulator Experiment has dem- vironment and the National Transport onstrated its potential for the study of in- Code Collaboration Modules Library are tense ion beams by containing an intense providing models for future national and single-species cesium plasma for more international collaboration in computa- than 300 msec, the equivalent of 20 km tional plasma physics. of travel in an accelerator. All of the exciting results discussed here This has been a banner year for theory would not have been possible without the and computation at PPPL as well. Break- consistent support of our Engineering and through understanding was achieved in Technical Infrastructure, as well as Envi- the role of turbulence “spreading” to ex- ronment, Safety, and Health teams. We are plain the transition between Bohm (unfa- especially pleased at the successful rede- vorable) and gyro-Bohm (favorable) con- sign and manufacture of the NSTX toroi- fi nement scaling, as plasma systems get dal-fi eld central bundle and joints, which larger in the most powerful simulations. promises to support a full and exciting New advances were made in understand- experimental run in FY04. We also con- ing MHD stability, particularly in the tinue to put the highest priority on safety presence of fast ions. For example, the con- at PPPL. With continued leadership sup- nection between the Global and Compres- port, as we had in FY03, we will need all sion Alfvén Eigenmode instabilities was hands on deck, healthy and energized, to elucidated on NSTX. Another dramatic accomplish our ambitious goals.

viii National Spherical Torus Experiment

National Spherical Torus Experiment

ith the National Spherical engineering aspects of the spherical to- Torus Experiment (NSTX) rus (ST) magnetic confi nement confi gu- W poised to begin physics ex- ration. periments in earnest after several weeks The failure occurred on February 14, of discharge development and device and 2003, following the morning test shots. auxiliary heating systems conditioning, Analysis of the event identifi ed shortcom- the experimental run was unexpected- ings in the structural design of the joint ly terminated due to a failure of the to- which led to failure after some 7,200 ma- roidal-fi eld (TF) lower inner leg-to-fl ag chine pulses, with a limited number at the joint. As depicted in Figure 1, the fl ag full rating of 6 kG. As shown in Figure 2, joint provides a removable connection be- the stiffness of the hub assembly was not tween the inner and outer TF leg assem- adequate, and repeated application of the blies, which permits removal of the entire electromagnetic loads led to unanticipat- TF inner leg and center stack assembly ed loads in the bolts, and high local cur- for maintenance. The demountable TF rent density that eventually led to failure assembly is one of the most challenging of the assembly.

1 Figure 1. Isometric view of the NSTX showing demountable toroidal-fi eld coil and toroidal-fi eld fl ag joint.

Due to the extensive damage, it was • shear keys are added to resist the not possible to recover the original TF vertical electromagnetic force, inner leg assembly. Furthermore, it was and clear that an improved design was needed. Therefore a recovery effort was initi- • voltage probes are provided in-situ ated, beginning with the development of to measure the resistance of every a new design. The new design (Figure 3) joint. incorporates features that address all of the shortcomings of the original design, Unanticipated Deflection including the following: Bolt Loads of Hub (typical) EM Assembly Load Hub Assembly • hub assembly stiffness is dramatical- TF ly increased, Bundle

• ﬂ ags are contained in steel boxes High Preload Current (bolts) with injected epoxy ﬁ lling the space Density between, Hub Assembly

• fl ag fasteners are larger diameter Figure 2. Repeated application of electro- and tightened to twice the force of magnetic loads led to structural failure of the original, lower toroidal-fi eld fl ag joint.

2 ly anticipated. Although the failure was unfortunate, it has led to an improved understanding of the TF joint behavior which is directly applicable to the design of next-step ST devices. Upgrades and Outage Maintenance Activities Taking advantage of the longer outage schedule due to the TF repair, the NSTX engineering and research operations teams were able to perform a number of important upgrades and preventive maintenance tasks above and beyond what a normal outage would permit. The outage enabled the neutral-beam- Figure 3. Isometric view of the new toroi- injection (NBI) team to repair the duct dal-fi eld fl ag joint from a CAD model. bellows which had developed intermittent leaks, particularly during bakeout. Extensive engineering resources were This repair will improve the effectiveness applied to the redesign effort to ensure a of bakeout cycles and speed the return to successful outcome while minimizing the normal operation after major openings. time duration of the recovery period. Fi- The NBI team also utilized this opportu- nite element analysis was performed to nity to perform preventive maintenance develop an understanding of the struc- on the main NBI torus isolation valve tural and thermal behavior of the joint and a compressor in the helium refriger- and to guide the development of the new ator. The team also replaced the NSTX design. Two technical reviews were con- control room fl oor tiles to address safe- ducted by teams of magnet experts from ty issues. In addition to these tasks, the other fusion laboratories. Tests were per- NBI team contributed strongly to the formed to characterize the electrical resis- TF repair work as needed. The radio-fre- tivity of the joint versus pressure, the fric- quency (rf) operations team has worked tion coeffi cient of the joint, the pull-out on the improvement and maintenance of strength of the fasteners, and other fea- the High-harmonic Fast-wave (HHFW) tures. In addition, a mechanical proto- system. type was exercised at the rated number of During a normal machine outage, cycles of full mechanical loads at elevated the diagnostic operations team typical- temperature, and an electrical prototype ly performs about three weeks of post- was tested at full current for the full-time run diagnostic calibrations. Because duration at full mechanical loads. of the extended outage, the diagnostic Based on the new design, the success- team was able to perform more extensive ful prototype testing, and the improved calibrations, including detailed spatial instrumentation that includes a new fi - and photometric calibrations of multi- ber-optic strain, temperature, and dis- pulse Thomson scattering, the newly in- placement monitoring system, reliable stalled 51-channel Charge-exchange Re- operation at full-rated parameters is ful- combination Spectroscopy (CHERS),

3 and the edge rotation diagnostics. Us- NSTX. PCI digitizers and signal condi- ing the vacuum-vessel bakeout system, tioning boards were also designed for use the divertor infrared (IR) camera was in this control system for an inexpensive calibrated for analyzing the heat loads data acquisition framework which does on the divertor plasma-facing compo- not depend on CAMAC. nents (PFCs). Detailed measurements were made of the geometry of the resis- Physics Research tive wall mode (RWM) detection coils During the shortened FY03 experi- and the sightlines of the neutral-particle mental campaign, plasma experiments analyzer. The frequency response of the were performed on 22 days with 488 suc- Mirnov coils was also measured. A num- cessful plasma discharges. Two hundred ber of diagnostic improvements were and nine discharges were with NBI heat- made. The RWM sensor shielding was ing and 140 with radio-frequency heat- improved against radio-frequency picking. A total of eight NSTX experimental up. The upper and lower secondary pas- proposals and seven machine propos- sive plate fl ux loops were repaired and als received experimental run time. The improved in preparation for the higher facility rapidly returned to reliable plas- elongation plasma expected in the FY04 ma operation in FY03, as evidenced by run. Preparations for the future deploy- the achievement of long-pulse double- ment of the poloidal CHERS diagnostic null divertor discharges at high plasma and a neutron collimator were also ac- current (1 MA, 0.35 s fl attop duration). celerated. Despite the shortened run, a number of In the area of research facility up- key tasks were accomplished in addition grades, more extensive laboratory work to making several important experimen- was performed to characterize and opti- tal observations. Furthermore, the pro- mize the multi-barrel lithium pellet in- longed outage gave researchers the op- jector and the supersonic gas injector to portunity to analyze and understand the be ready for the FY04 run. To implement previous years’ data more fully. the recently discovered “transient coaxi- Considerable progress towards facili- al helicity injection (CHI)” technique in tating more fi nely tuned plasma equilib- collaboration with the Helicity Inject- rium control was made through commis- ed Torus (HIT-II) group at the Universi- sioning of the real-time EFIT (rtEFIT) ty of Washington, Seattle, WA, a new ca- code. Good agreement was obtained be- pacitor bank power supply was designed tween the plasma equilibrium deter- and will be implemented in FY04. Final- mined by the rtEFIT code and the more ly, in preparation for the FY04 campaign sophisticated implementation of EFIT to achieve higher plasma elongation, the run on a more extensive set of input data time response of the NSTX real-time between discharges. Double-null diver- plasma control system was signifi cantly tor discharges were developed with all the improved by reducing the time delay by poloidal-fi eld currents controlled in real- a factor of four. time to match a preprogrammed shape The extended outage also allowed the for the plasma boundary. This work implementation of a Peripheral Com- helped pave the way for developing other ponent Interconnect (PCI)-based tim- plasma shapes and the more sophisticat- ing system, fully compatible with the ed forms of control needed to reach the CAMAC-based system now in use on project’s experimental goals.

4 In the area of noninductive plasma Fascinating behavior in the plasma edge start-up, the capability for CHI was re- was observed during HHFW heating by established with the new absorber insu- a new diagnostic, the Edge Rotation Di- lator that had been installed in the pre- agnostic (ERD), which simultaneous- ceding outage. Using the prescription ly measures the poloidal and toroidal ro- developed in earlier experiments, toroi- tation, temperature, and density of both dal currents up to 150 kA were produced C2+ and He+1 ions at the plasma edge. in discharges lasting up to 150 ms. A new The diagnostic uncovered an unsuspect- “transient CHI” technique, developed on ed coupling between the launched radio- the HIT-II device, was tested for the fi rst frequency waves and the edge ions. A hot time in NSTX. Short pulses of CHI were (~0.5 keV), poloidally rotating (50 km/s) obtained on some discharges, and im- component of the majority helium ions provements needed to the control of the was seen to develop over a period of CHI power supply were identifi ed. about 300 ms during HHFW heating Following the modifi cations to the ra- (Figure 4), but then decayed rapidly over dio-frequency power feed-throughs of 30 ms after the HHFW was switched off. the NSTX antenna during the 2002 out- The temperature of the hot component age, the performance of the HHFW heat- was higher when viewed poloidally than ing system improved markedly. Anten- toroidally. It is believed that parametric na voltages up to 15 kV were achieved decay of the HHFW wave was responsi- compared to a limit of 12 kV in the pre- ble for the heating, and tests to verify this vious experimental run. The highest hypothesis are planned for the FY04 ex- HHFW power was 5.1 MW and there perimental campaign. were 29 discharges with power above During the FY02 outage, a reposition- 3 MW. Good electron heating was ob- ing of the poloidal-fi eld coil that provides served, producing peak electron temper- the vertical fi eld eliminated an error fi eld atures above 2.5 keV. With early appli- caused by this coil. This error fi eld had cation of the radio-frequency power, the given rise to mode-locking that severely temperature rise was slow, but the elec- impacted plasma performance. The re- tron temperature profi le then remained duction of the error fi eld reduced dra- peaked for about 50 ms. The HHFW current-drive experi- -1 ments were carried out at k|| = 7.6 m , Poloidal View and the results of co-versus-counter an- 600 tenna-phasing comparisons indicated He II 4686 Å loop voltage differences of approximately 400 200 to 300 mV lasting for 200 ms. Mod- Hot eling of these experiments indicated that 200 an radio-frequency-driven current differ- Cold ence (co-versus-counter) of ~100 kA was

Ion Temperature (eV) Ion Temperature 0 consistent with this voltage difference, demonstrating the ability of the radio- 012345 Radio-frequency Power (MW) frequency to drive sustained current. Fu- ture experiments will focus on develop- Figure 4. The hot and cold temperature ing the means to increase the amount of components of HeII measured at the plas- driven current. ma edge by the Edge Rotation Diagnostic.

5 matically, but did not eliminate entire- the high density and broad density pro- ly, the mode-locking, and the dynamics fi le characteristic of H-modes cause the of these MHD modes were investigated. loss through the following mechanism: In ohmically heated plasmas, the locking the evolution of the current profi le de- of a rotating tearing mode was found to stabilizes pressure-driven low-n MHD be very sensitive to plasma density. A de- activity (n is the toroidal mode number) crease of the line-average density by less while the beam deposition profi le broad- than 5% caused a mode, initially rotat- ens to feed trapped ions into the region ing in the counter-plasma-current direc- where they can be expelled by the MHD tion, to lock and grow. When neutral- activity. beam heating was added, the mode grew Theory and modeling advances have more rapidly and locked sooner, possibly led to a better understanding of the equi- because the accompanying beam torque librium and stability properties of NSTX opposed the intrinsic mode rotation. plasmas; of particular importance is the The effect of MHD activity on the role of the observed rapid rotation. For confi nement of fast ions was studied un- instance, the large in-out asymmetry in der a variety of conditions using the Neu- the measured density profi le is consis- tral Particle Analyzer (NPA) diagnostic. tent with a simple MHD force balance Rapid ion heating of the fast particles that includes the measured rotation- was observed in the NPA spectrum fol- al effects. Because of the importance of lowing reconnection events in NSTX. this rotation, the EFIT magnetic recon- In ohmically heated plasmas, both deu- struction code has been upgraded to in- terium (the majority ion) and hydrogen clude this measurement, as well as other (a minority ion, 2-5%) neutral particles plasma properties, as a constraint. Fig- showed nearly Maxwellian tails with ef- ure 5 shows the fl ux surfaces and pres- fective temperatures of 1-4 keV after a re- sure surfaces computed by this upgrad- connection event, compared with a tem- ed EFIT code; the effect of the rotation perature typically 0.3 keV before the is seen in the shift of the pressure surfaces event. In neutral-beam-heated plasmas, with respect to the fl ux surfaces. A com- the deuterium spectrum showed an ef- plementary approach has been to devel- fective tail temperature up to 8 keV fol- op the FLOW code in collaboration with lowing the reconnection event, and it is the University of Rochester in New York, possible that a redistribution of unther- which also solves for the internal equilib- malized beam ions contributed to the rium using plasma, beam, and rotation apparent tail in this case. The NPA also profi les. While EFIT is a free-boundary observed accelerated MHD-induced en- solution, FLOW is fi xed boundary. ergetic ion loss in NSTX high-confi ne- NSTX has achieved high toroidal beta ment mode (H-mode) discharges. The up to 35% and high normalized beta up magnitude of this loss decreased with to 6.5. Experiments have shown a modest increasing neutral-beam-injection en- increase of the achievable beta with trian- ergy, toroidal fi eld, and tangency radius gularity (at constant elongation) over the of the NPA sightline. Increasing each of range from δ = 0.4 to 0.8. The highest these parameters reduced the fraction of toroidal beta discharges obtained at high trapped particles that is either present in normalized current are computed to be the plasma or viewed by the NPA. The ideally unstable to n = 1 pressure-driv- TRANSP code modeling suggests that en internal kink instabilities, and experi-

6 nonlinear phase fi nd that the fl ow profi le typically fl attens during the reconnection process, consistent with the measured evolution of the rotation profi le from the charge-exchange recombination diagnostic. Rapid rotation, large initial rotational shear, and potentially reduced MHD linear growth rates in high-beta ST plasmas are all likely to contribute to the nonlinear saturation of core kink instabilities at beta values above the no-wall limit.. NSTX experiments revealed a rich variety of beam-driven Alfvén instabilities over a wide range of frequencies. In the sub-ion cyclotron frequency range (≤1 MHz), global Alfvén eigenmodes have been simulated using the HYM code. Results of these calculations show that the most unstable modes are at low- to-moderate toroidal mode number, and they can have a large compressional component near the edge. The M3D code was recently enhanced to handle generalized 3-D geometry. M3D was used to study toroidal Alfvén instabili- Figure 5. The EFIT code reconstruction ties (~100’s kHz), and linear calculations of NSTX plasma showing the fl ux surfac- showed that the dominant n = 2 mode es (black) and surfaces of constant pressure frequency “chirps” down as it moves out (white). radially (Figure 6), consistent with experimental observations. Initial non- mentally the onset of m/n = 1/1 activity linear simulations with multiple modes is observed near the computed instabili- show similar behavior. ty threshold. However, these instabilities can saturate in amplitude for beta values well above the computed ideal no- wall limit. An important element in this saturation above the no-wall limit appears to be the high toroidal rotation and strong rotational shear in some plasmas with neutral-beam heating. The multilevel physics, massively-parallel simulation code M3D has been used to study these phenomena. Toroidal fl ow shear is calculated to reduce the linear growth Figure 6. Linear (left) and nonlinear (right) rate of the internal kink by up to a fac- mode structure of n=2 toroidal Alfvén eigen- tor of three. Simulations carried into the mode mode as computed by M3D code.

7 Signifi cant progress has also been transport coeffi cients within the spatial made in understanding the confi nement region from r/a = 0.2 to 0.65. Outside and transport properties of NSTX plas- this region, however, large uncertainties mas. Local transport analysis, using the make it diffi cult to draw any conclusions. TRANSP code, has been performed on Within the high confi dence region, how- a large collection of both the low-con- ever, it is clear that electrons dominate fi nement mode (L-mode) and H-mode the heat loss in NBI-heated discharges, discharges. Fast-ion stored energies and with χi << χe where χi and χe are the ion losses are calculated by TRANSP, and and electron thermal diffusivity time, re- this allows the determination of thermal spectively (see Figure 8). The ion thermal energy confi nement times. These results diffusivity is at or above the level predict- are shown in Figure 7, where the thermal ed by neoclassical theory. energy confi nement time (τE) is plotted Uncertainties in the core and edge ther- against the ITER H-mode scaling value. mal transport coeffi cients will most like- As can be seen, H-mode discharges on ly be reduced using data from a new, 51- average have higher τE’s than L-modes, channel CHERS diagnostic, which was reaching values of approximately 30% commissioned and took data during the over the scaling value. abbreviated run. The data has been ana- Detailed studies were undertaken to lyzed during the outage, taking into ac- determine the transport coeffi cients and count the complex structure observed in their uncertainties for the electrons and the distribution of the background emis- the ions using the most up-to-date set of sion and including various atomic phys- reduced data and physics assumptions. ics corrections that become signifi cant in Uncertainties in the thermal diffusivities the plasma conditions of NSTX. are generated by uncertainties in the data A regime of improved electron con- and their gradients as well as in the plas- fi nement, in which the core χe decreased ma equilibrium and data mappings. The several fold, was observed in low-densi- results of this uncertainty analysis indi- ty L-mode discharges with early neutral- cate a high level of confi dence in the heat beam injection. Analysis of the ultrasoft X-ray data, as well as TRANSP code calculations using magnetic diffusion, indicates the formation of a region of low 0.08 or negative magnetic shear in the core of these discharges. At the same time as the 0.06 reduction in electron transport, a signifi - cant increase is estimated in the ion ther- 0.04 mal and particle transport. The energy confi nement in the low-density/shear- 0.02 L-mode reversed NSTX discharges signifi cant- H-mode 0 ly increased compared to the normal sit- 0 0.02 0.04 0.06 0.08 uation, possibly opening a path towards

Thermal Energy Confinement Time (sec) Thermal Energy Confinement Time ITER H-mode Scaling Value (sec) high-performance ST regimes. Figure 7. Experimental thermal energy con- The basis of energy and particle trans- ﬁ nement time plotted against the ITER port processes in these L- and H-mode scaling value for L-mode (blue) and H- experiments on NSTX was examined mode (red) plasmas. with ﬂ ux tube geometry, gyrokinetic sim-

8 100 and the boundary conditions for global r/a = 0.4

/sec) conﬁ nement. Experiments and analysis 2 were performed to study the edge plas- 10 ma characteristics, including fueling and turbulence, and to develop techniques to study and control the particle and power 1 deposition on plasma-facing components. This last issue was addressed by measur- L-mode ing hydrocarbon deposition on plasma- H-mode facing surfaces using two quartz-crystal

Ion Thermal Diffusivity (m Ion Thermal Diffusivity 0.1 0.1 110100 microbalances installed 0.77 m outside Electron Thermal Diffusivity (m2/sec) the last closed fl ux surface of NSTX in a confi guration that mimics a typical diag- Figure 8. Ion thermal diffusivity confi ne- nostic window or mirror. Time-resolved ment time plotted against the electron ther- measurements over the FY03 experimen- mal diffusivity confi nement time for L- mode (blue) and H-mode (red) plasmas. tal run recorded a total of 123 nm of deposition on the exposed surface. Inter- estingly, however, 67 nm of material loss ulations using the massively parallel code occurred in seven discharges. Ion beam GS2. Linear microinstability calculations analysis showed the deposits to be dom- performed with GS2 predict strong sup- inantly composed of carbon, oxygen, pression of short-wavelength electron and deuterium. The net deposited mass temperature gradient (ETG) modes by of 13.5 µg/m2 matched the deposition low or negative magnetic shear in the monitor measurements results within the core, consistent with the improvement 10% experimental uncertainty. of core electron confi nement in the low An experiment was conducted to mea- density, NBI-heated L-mode plasmas. sure the effect of the location of the gas Near the edge in the H-mode plasmas, injector on H-mode access and quality. the ETG modes are found to be unstable, For the lower-single null divertor con- as are microtearing modes. Microtearing fi guration, good H-modes were reestab- modes have never been found to be the lished with gas injection from the center- fastest growing mode in any experimen- stack at the midplane, but not from the tal tokamak simulations, but they appear center-stack upper corner, the outboard to be such in NSTX simulations. Their midplane, or the lower divertor X-point connection with high electron transport locations, confi rming that injector poloi- losses has been hypothesized for decades dal location does affect H-mode access. and is the subject of intense present re- In contrast, for the double-null divertor search. In both the L- and the H-mode confi guration, H-modes were obtained cases, the long-wavelength ion tempera- with fueling from either the midplane or ture gradient (ITG) modes are predicted upper corner on the center stack, indicat- to be likely stabilized by the strong rota- ing that H-mode quality and access are tional shear, consistent with the inference less sensitive to fueling variations along that the ion thermal diffusivity is near the the center stack for this confi guration. neoclassical value. Edge toroidal rotation was higher (more The edge plasma is important since it co-plasma current) just prior to the L-H determines the plasma-wall interaction transition time for fueling from the cen-

9 ter-stack midplane location than the oth- ing the BOUT three-dimensional turbu- er locations in lower-single null confi g- lence code by Lawrence Livermore Na- uration, qualitatively consistent with a tional Laboratory. recent neoclassical theory and Monte- Gas puff imaging, or GPI, experiments Carlo calculations. on NSTX provided information on edge Another experiment was conduct- turbulence and spatial structures, and they ed to control the density rise during the also provided an interesting challenge to H-mode phase by pre-conditioning the theory and modeling. The DEGAS 2 plasma contact area with a series of he- Monte Carlo neutral transport code was lium discharges. The conditioning dis- used to simulate helium atom behavior charges produced a modest 40% re- in these measurements on NSTX. These duction in Dα-line emission which is detailed simulations permit direct com- a measure of the deuterium infl ux, and parison of the code output with the im- some reduction was observed during the ages obtained from the GPI camera. Vi- H-mode phase on the density at the in- sualizations of the information input to ner “ear” of the profi le measured by the and output from DEGAS 2 have provid- Thomson scattering diagnostic. A larg- ed a better understanding of the spatial er Dα reduction was obtained following relationships of the physical objects, such helium discharges heated by HHFW in as convective cell structures, in the exper- which the current ramp down was con- iment (Figure 9). trolled to avoid a terminal reconnection event. It appears these reconnection Collaborations and events may undo the benefi cial effect of International Cooperation helium conditioning. In addition to PPPL scientists, the Plasma fl uctuations and transport at NSTX research team comprises research- the edge of NSTX have recently been ers from more than 30 institutions both measured with various diagnostics, and in the United States and abroad. For ex- it was found that the edge was normally ample, researchers from Japan, China, very turbulent, at least near the outer mid- Italy, France, the United Kingdom, Is- plane. Consequently, the cross-fi eld edge rael, and South Korea, have all been in- particle and heat transport is normally volved in NSTX experiments during the very large, which is actually favorable for past several years. These scientists are in- reducing the local heat load on the diver- volved in diagnostic development, nu- tor plate surfaces. Langmuir probe mea- merical simulation and analysis, enabling surements by the University of California technology development, machine oper- at San Diego group have shown that these ation, and research program planning. edge fl uctuations in NSTX were strongly Some of the major facility and diagnostic “intermittent” and often had fl uctuation contributions that had signifi cant collab- levels near 100% in the scrape-off layer. orator involvement include: These fl uctuations have also been seen with the gas puff imaging diagnostic as • installation of a new insulator and localized coherent structures that formed set of coils for CHI, in the edge and moved outward at high speed. Such data from NSTX is being • modifi cation of power feed-throughs analyzed and compared with theoretical for the high harmonic fast wave an- simulations of edge turbulence made us- tenna,

10 587.6 nm Neutral Helium Emission Density Isosurface Cloud

Helium Density Contour Outlines Simulated Manifold

Field-line-following Electron Density Perturbation

Electron Density Contours on Z = Constant and Corners of Y = Constant Planes Camera View

Figure 9. Experimental setup for viewing and modeling clouds of neutral density using the Gas Puff Imaging Diagnostic.

• installation of a supersonic gas in- The NSTX program also had strong jector for fueling control, ties to other projects both nationally and • design of an active control system internationally. NSTX researchers par- for reducing stray magnetic fi elds ticipated actively on ST-related experi- and for suppressing beta-limiting ments at the University of Washington external modes, (HIT-II), at PPPL [Current-Drive Ex- periment-Upgrade (CDX-U), and in the • design of Motional Stark Effect di- United Kingdom [Mega-ampere Spher- agnostic for measuring the plasma ical Torus (MAST)]. There was strong current profi le, participation by NSTX researchers in the • development of the real-time EFIT International Tokamak Physics Activities control algorithm, as part of the ITER process. • upgrades to interferometers, refl ec- The NSTX Research Plan tometers, and reciprocating probe In FY03, the NSTX research team de- for profi le and fl uctuation measure- veloped a fi ve-year plan. This activity ments, and sharpened the vision of NSTX research, • installation of Langmuir probe ar- in part by quantifying the research tool rays for diagnosing scrape-off plas- requirements. Following a strong en- ma characteristics. dorsement from an international review

11 panel, the plan is being implemented and • Neutron collimator array to mea- is aimed in part at developing the science sure the beam ion deposition profi le for demonstrating ambitious research and for power balance studies. performance goals during a fi ve-year period from 2004 through 2008, assuming • Higher time resolution (90 Hz) that the budgetary support is similar to and spatial resolution (30 channels) that assumed for the planning process. Thomson scattering diagnostic for The research program set out in the electron temperature and density fi ve-year plan consists of three phases: profi le measurements. Microwave imaging refl ectometry 1. Extending the stable operating space • to measure long-wavelength (ion- and duration of the pulse length of temperature-gradient mode) tur- high-confi nement high-beta plas- bulence, and microwave scattering mas and developing the basis for to measure short-wavelength (elec- fully solenoid-free plasma start-up tron-temperature-gradient mode) and sustainment. MHD modes will turbulence. be passively stabilized with the assistance of driven rotation. • Poloidally viewing Charge-Ex- 2. Developing advanced control tools change Recombination Spectros- to optimize further high-beta plas- copy diagnostic to measure poloi- ma performance. Detailed experi- dal rotation velocities for fl ow shear ment/theory comparisons and ad- studies. vanced diagnostics will also be the Facility Upgrades cornerstones in developing a scientifi c basis for this development. • Coil sets to control actively stray error fi elds and external MHD. 3. Integrating solenoid-free start-up and sustainment and control strat- • Reconfi guration of the passive plates egies for generating high-beta plas- for enhanced vertical stability con- mas to enable long-pulse high-control. fi nement high-beta operations. • Electron-Bernstein waves as a tool The upgrades required to support the for local noninductive current drive. achievement of these goals can be divid- • Cryopump and/or lithium surface ed into three categories: module for active particle and density control. Diagnostic Upgrades • Motional Stark Effect to measure • Deuterium pellet injection for core current profi le modifi cations from fueling and profi le modifi cation. both inductive and noninductive Plasma Control current drive processes, and the radial electric fi eld for fl ow shear stud- • Further development of the iso- ies. fl ux control algorithm of the real- time EFIT code to improve bound- • Very high toroidal mode number ary shape control during the plasma magnetics. discharge.

12 In addition to these upgrades, devel- were made on NSTX in February 2003. opment of theoretical and modeling However, these were interrupted by the tools, along with increased theory/exper- early termination of the fi scal year 2003 iment coupling in all physics areas will NSTX experimental campaign. The mea- help develop the understanding to allow surements will be resumed in February/ us to achieve more easily our integrated March 2004. programmatic goals. The break in the NSTX research schedule was used for upgrades of the spec- NSTX Astrophysics Project trometer’s vacuum system and to publish The goal of this astrophysics project or submit for publication several articles is to measure density-sensitive line ratios on stellar fl are plasmas. (See the Publica- from helium- and neon-like ions, which tions section of this Annual Highlights are used for the diagnosis of stellar fl ares, Report for a listing of these and other rel- in a controlled plasma environment with- evant papers.) In particular, a thin foil in the NSTX. was installed to separate the NSTX vacu- For this purpose, a high-resolution um from the spectrometer vacuum. This X-ray crystal spectrometer covering the will prevent a pressure increase inside the wavelength range from 4 to 24 Å was in- spectrometer during hydrogen pre-fi ll of stalled at NSTX with a PC-based data the NSTX vacuum vessel that was noted acquisition system. First measurements during the operation in February 2003.

13 14 CCurrenturrent DDriverive EExperiment-Upgradexperiment-Upgrade

FFillingilling thethe liquidliquid lithiumlithium ttrayray llimiterimiter inin tthehe CurrentCurrent DDriverive EExperiment-Upgrade.xperiment-Upgrade.

echnological progress and ad- antee survivability under conditions of vances in fusion science have al- repetitive micropellet ignition and burn. T ways gone hand-in-hand. One of However, fl owing liquid-metal walls have the major technological problems facing only recently been proposed for magnet- the eventual commercial development of ic fusion. In a spherical torus or a toka- fusion energy is the design of a reactor mak, a fl owing metal wall of liquid lith- wall that can survive the high heat and ium may provide not only heat removal, neutron fl uxes generated by an ignited but plasma stabilization to unprecedent- plasma. A novel and exciting recent de- ed high values of plasma beta, which is a velopment which promises to solve this measure of the plasma pressure relative to longstanding engineering problem, while that of the confi ning magnetic fi eld. offering great physics benefi ts, is the de- Liquid-lithium walls would also great- velopment of the liquid-metal wall con- ly reduce the uncontrolled recycling of cept. cold gas back into the plasma edge, thus Reactor designs for inertial fusion re- promising high plasma performance un- actors have relied for some time on the der reactor conditions. Production of concept of a fl owing liquid wall to guar- high-performance plasmas with lithium-

15 coated walls was fi rst tested on the To- Facility Description kamak Fusion Test Reactor (TFTR) and The CDX-U is a small spherical to- resulted in the highest fusion power and rus (ST), with a major radius of 34 cm, gain (QDT) obtained on that device. All a minor radius of 22 cm, and a plasma these factors combine to make the con- elongation of 1.6. The toroidal fi eld is cept of a tokamak reactor with fl owing 2.2 kG, and the maximum plasma cur- liquid-lithium walls very attractive for fu- rent is 100 kA. The plasma pulse length sion energy production. is limited to 20 ms by the ohmic power The Current Drive Experiment-Up- supply, which is used to drive the plasma grade (CDX-U), Figure 1, was the current inductively. This supply is under- world’s fi rst fusion experiment to oper- going the fi rst of a series of upgrades that ate with large area liquid-lithium plas- will increase both the maximum plasma ma-facing components (PFCs). The current and the pulse duration. Although liquid-lithium PFC program involves the ohmic power supply is based on a ca- collaborations with numerous universi- pacitor bank, the toroidal-fi eld coils and ties and national laboratories, including the poloidal-fi eld coil set are powered by the University of California at San Di- six large 12-phase computer-controlled ego (UCSD), Oak Ridge National Lab- power supplies which can provide up to oratory (ORNL), Sandia National Lab- 18 MW for several hundred ms. Radio- oratories, and the Lawrence Livermore frequency power of 300 kW at 8 MHz is National Laboratory. Other institutions also available for auxiliary heating. Diag- are also participating through the Energy nostics for the device include a 12-point Advanced Liquid Plasma-facing Surface Thomson scattering system, a 140-GHz (ALPS) and Advanced Power Extraction interferometer, a number of Langmuir (APEX) programs of the U.S. Depart- probes, and many edge and core plasma ment of Energy (DOE). spectroscopic diagnostics covering the

FFigureigure 1.1. CurrentCurrent DriveDrive EExperiment-Upgrade.xperiment-Upgrade.

16 visible to soft X-ray regions of the spec- and were instrumental in identifying nu- trum. merous problems and safety concerns with lithium operations. However, the Experiments surface area of the rail limiter was small with Lithium Limiters (approximately 300 cm2, less than half of The fi rst experiments involving the use which is in contact with the plasma), and of solid and liquid lithium as a plasma so the effects of the lithium-coated limit- limiter in CDX-U took place in FY00, er on the discharge itself were minimal. utilizing a lithium-covered rail 5 cm in In FY01 the lithium PFC experiments on diameter and 20-cm long, which was de- CDX-U entered a second phase, when veloped at UCSD. The lithium limiter the toroidal liquid-lithium belt limiter was inserted or removed via a double gate was placed in operation. valve airlock system to prevent exposure The toroidal belt limiter is shown in of the lithium to air. When the limiter Figure 2. It consists of a shallow, heated was fully inserted, it formed the upper toroidal tray, with a radius of 34 cm and a limiting surface for the plasma discharge width of 10 cm, which is fi lled with lithi- and was intended to defi ne the last closed um to a depth of a few millimeters. If com- fl ux surface for the discharge. When the pletely fi lled with lithium, the belt limit- limiter was retracted, ceramic boron car- er presents an exposed area of 2,000 cm2 bide rods formed the upper limiting sur- to the plasma. First operation of CDX-U face for the discharge. The limiter had an with the lithium belt limiter yielded clear internal heater and was operated in con- indications of the ability of a liquid-lith- tact with the plasma over the tempera- ium limiter to reduce impurities, despite ture range of 20-300 °C. diffi culties in obtaining a uniform fi ll of The rail limiter experiments demon- the tray with lithium and the rapid devel- strated that an ST plasma could success- opment of oxide and hydroxide layers on fully operate with a liquid-lithium PFC the surface of the lithium.

FFigureigure 22.. InteriorInterior ofof thethe CCDX-UDX-U sshowinghowing tthehe ((empty)empty) ttoroidaloroidal lliquid-lithiumiquid-lithium bbeltelt llimiter.imiter.

17 During the fi rst lithium tray campaign fi lling process is used as the frontispiece (FY02-03) the tray was loaded with solid to this report. The liquid-lithium injec- lithium at room temperature, after which tor is the cylindrical object entering the it was heated to 300 °C to melt the lithi- fi eld of view from the upper right. um (which melts at 180 °C). This method This approach proved very success- of fi lling the tray proved diffi cult and re- ful. The lithium immediately covered sulted in incomplete coverage of the tray 80% of the tray with visibly clean, metal- with lithium, as well as oxidized surface lic lithium. Subsequent cycles of heating conditions. It is estimated that at most and discharge cleaning led to 100% tray 50% of the tray was covered with lithi- coverage with the highly refl ective liquid um. Despite these diffi culties, the prima- metal. ry predictions for the utility of lithium as The liquid-lithium fi ll had an imme- a plasma-facing component were verifi ed. diate effect on CDX-U plasma oper- Plasma recycling was reduced to very low ations, as indicated by the plot of plas- levels at the surface of the lithium. The ma discharge peak current versus time impurity content of lithium-limited dis- of discharge in Figure 3. For the sever- charges dropped signifi cantly. These real weeks of plasma operations prior to sults provided motivation for further ef- the lithium fi ll, plasma current was lim- forts to improve the quality and quantity ited to less than 60 kA. Within a half- of the liquid-lithium PFC in CDX-U. hour of resuming plasma operations af- In FY03 CDX-U was vented, the lim- ter the lithium fi ll, the maximum plasma iter tray and vessel interior were cleaned, current had increased to nearly 80 kA. In and the tray was reinstalled in the vac- addition, the amount of deuterium gas uum vessel. A new lithium-fi lling tech- required to fuel the plasma increased by nique was tested at UCSD and imple- a factor of four, indicating that recycling mented on CDX-U. This new approach on the liquid lithium was signifi cantly re- involved injecting liquid lithium onto a duced, in comparison to the bare tray. very hot (500 °C) tray to obtain imme- A photograph of the tray taken imme- diate wetting and spreading of the liquid diately after the fi rst day of plasma op- lithium in the tray. A photograph of the erations is shown in Figure 4. It is clear

Lithium Fill at 1430 May 5, 2003

60 Tray Cooled 40 to 260 °C

20 2 May 2003 5 May 2003 Bare Tray Liquid Lithium in Tray Peak Plasma Current (kA) 0 900 1100 1300 1900 2100 2300 2500 Time of Discharge Time of Discharge FFigureigure 3.3. PeakPeak plasmaplasma currentcurrent asas a functionfunction ofof plasmaplasma dischargedischarge timetime forfor anan experimentalexperimental rrunun pprecedingreceding tthehe llithiumithium ttrayray aandnd fforor a rrunun iimmediatelymmediately ffollowingollowing tthehe ttrayray ﬁ ll.ll.

18 FFigureigure 44.. TThehe lliquid-lithiumiquid-lithium fi llledled ttrayray llimiterimiter aafterfter 4400 pplasmalasma ddischarges.ischarges. that no surface coatings were formed as lithium fi lm system is also prototypical a result of the 40 plasma discharges per- of the wall design for the Lithium Toka- formed, indicating that any lithium deu- mak Experiment (LTX), presently being teride impurity which formed as a result designed. The CDX-U will be disassem- of plasma contact remained dissolved in bled at the end of FY05, and LTX (to be the liquid lithium. operational in FY06) will be installed in The effect of a large liquid lithium its place. The LTX will explore tokamak PFC on the loop voltage required to plasma operations with a fully nonrecy- maintain the plasma current and on the cling liquid lithium wall. gas required to fuel the plasma is indicated in Figure 5. The loop voltage required to maintain the plasma current drops by Collaborations a factor of four or more for the lithium and Graduate Studies discharge. Such a large reduction in loop The fi rst liquid-lithium system in- voltage is unprecedented in small toka- stalled in CDX-U was a rail limiter de- mak research. signed and constructed by collaborators at UCSD. The PISCES Group at UCSD Future Plans was closely involved with the rail limiter The last cycle of operations with the experiments, and designed the new lithi- lithium-fi lled tray will be completed in um fi lling system for the CDX-U limiter FY04. After tray experiments are com- tray. The UCSD personnel continue to pleted, the tray system will be removed participate in the lithium-fi lled tray ex- and replaced with a liquid-lithium-coat- periments. ed limiter system, which is prototypical Researchers at Sandia National Lab- of a divertor target system under consid- oratories have contributed surface anal- eration for the National Spherical Torus ysis of wall samples and have provided Experiment (NSTX). This thin liquid and set up an infrared camera to moni-

19 Fueling with Stainless Fueling with Liquid Steel Limiter Lithium Limiter 80 80

60 60

40 40

20 20

Plasma Current (kA) 0 0

4 4

2 2

0 0 Loop Voltage (V) Loop Voltage -2 -2

12 12 10 10 ) -3 8 8 cm

12 6 6

(10 4 4 2 2 Average Electron Density Average 0 0 6 6 Fueling

4 4 ) 19 10

x Prefill ( Only 2 Fuels Fueling 2

Number of Particles in CDX-U Number of Deuterium Atoms 0 0 0.21 0.22 0.23 0.21 0.22 0.23 Time Time FFigureigure 55.. TThehe uusese ooff a lliquid-lithiumiquid-lithium llimiterimiter rresultsesults iinn hhigherigher pplasmalasma ccurrents,urrents, llowerower vvoltageoltage rrequiredequired ttoo ddriverive tthehe ccurrenturrent ((greatergreater eefﬁfﬁ ciency),ciency), andand goodgood ddensityensity ccontrolontrol — ffuelingueling ooff tthehe pplasmalasma iiss nono llongeronger ddominatedominated bbyy uuncontrollablencontrollable pplasma-walllasma-wall iinteractions.nteractions. tor the surface temperature of the lithi- been participants in the experiments, and um during plasma discharges. Numerous they will continue to be involved in the other scientists in the DOE Advanced future. Liquid Plasma-facing Surface and Ad- The CDX-U Group and the Plas- vanced Power Extraction programs have ma Spectroscopy Group at Johns Hop-

20 kins University plan to continue their The Lithium Tokamak Experiment long-term collaboration in the area of ST (LTX) project will further involve UCSD diagnostic development. The CDX-U and ORNL. One of the co-principal in- Group also maintains ongoing collabora- vestigators for the LTX proposal is from tions with the University of Wisconsin at UCSD. A key feature of the LTX proj- Madison, the University of Tokyo in Ja- ect is core fueling of the plasma, which pan, the A.F. Ioffe Physical-Technical In- will be provided by a pellet injector con- stitute at St. Petersburg in the Russian structed at ORNL. Federation, and the Hebrew University A primary role of CDX-U has been to in Israel. In addition, CDX-U scientists serve as a training ground for students. have worked actively with ST researchers Presently three Princeton University from the Mega-Amp Spherical Tokamak graduate students, two from the Astro- (MAST) Experiment at Culham Labora- physical Sciences Department and one tory in England. from the Physics Department, are pur- A number of collaborations with suing research on CDX-U. Two of these ORNL are underway. These include an students intend to use the LTX for their ongoing collaboration on spectroscopic thesis topics. In 2003, two Drexel Uni- diagnostics of lithium and impurity con- versity students spent their co-op terms centrations at the lithium limiter. These working in the CDX-U Group. The in- diagnostics have proved invaluable for volvement of both graduate and under- measuring the effects of lithium on the graduate students will continue as the edge plasma. LTX becomes operational.

21 22 Magnetic Reconnection Experiment

Magnetic Reconnection Experiment

he Magnetic Reconnection Ex- connection rate is often greatly enhanced periment (MRX), shown above, over collision-based classical resistivity. T was built to study magnetic re- In nature, reconnection plays an impor- connection as a fundamental plasma pro- tant role in the evolution of solar fl ares, cess in a controlled laboratory environ- coronal heating, and in the dynamics of ment. Magnetic Reconnection — the the Earth’s magnetosphere. Reconnec- topological breaking, annihilation, and tion at the dayside magnetopause is of- reconnection of magnetic fi eld lines — ten considered as the onset and trigger of can occur in virtually all magnetized plas- such events as auroral substorms and geo- mas, both in the laboratory and in nature magnetic storms. In recent years, the so- (Figure 1). lar satellite TRACE has provided the best Despite its omnipresence, reconnec- views yet that reconnection is involved in tion is not a well-understood phenome- solar fl are energy release (Figure 2). How- non. In laboratory fusion plasmas, such ever, the rate of energy release is not well as tokamaks, reconnection manifests it- resolved by the present understanding of self as “sawtooth” oscillations in electron reconnection physics. The observed “fast temperature, affecting plasma confi ne- reconnection” has made magnetic recon- ment. In sawtooth oscillations, the re- nection a very active area of research.

23 t=t1 t=t2 >t1

Vin Vin

∆ VA VA

L Dissipation Region Figure 1. Evolution of the magnetic ﬁ eld lines during reconnection.

Experiments on the MRX have provid- jointly funded by the U.S. Department ed crucial data with which the theoretical of Energy, the National Science Founda- and observational research communities tion, and the National Aeronautics and can compare their work. Cross-disciplin- Space Administration. ary interactions have led to fertile discussions and useful reassessments of the Research Objectives present understanding. Indeed, experi- The primary purpose of the MRX is mental research on the MRX has created the comprehensive analysis of magnetic renewed interest in magnetic reconnec- reconnection and related physics, which tion unseen for some decades. are crucial for understanding self-organi- Because of the strong impact of MRX zation phenomena of fusion plasmas as research on many ﬁ elds of study, it is well as solar and magnetospheric plas-

Figure 2. Image of the sun taken by the TRACE satellite. [The TRACE (Transition Region and Coronal Explorer) satellite is a mission of the Stanford-Lockheed Institute for Space Re- search and part of the National Aeronautics and Space Administration Small Explorer Pro- gram.]

24 mas. The analysis focuses on the cou- gramming an applied external magnet- pling between local microscale features of ic fi eld. MRX was designed to achieve a the reconnection layer and global proper- variety of merging geometries and mag- ties such as external driving force, magnetic fi eld topologies. Two types of re- netohydrodynamic (MHD) fl ows, and connection have been studied: null-he- the evolution of plasma equilibrium. licity and co-helicity. In the former there The MRX has the following research is no toroidal magnetic fi eld in the re- goals: connection layer, and in the latter there is a sizable toroidal fi eld. Qualitative dif- • Experimentally test two-dimen- ferences in the reconnection layer arise sional (2-D) and three-dimensional depending on the presence of the toroi- (3-D) theoretical models of the re- dal fi eld. connection layer; A set of carefully chosen diagnostics • Investigate the role of non-MHD provides insight into the physics of mag- physics, including turbulence, in netic reconnection and real-time moni- the reconnection layer; toring of MRX plasmas. These include Langmuir probes (electron density and • Study global MHD issues including temperature), spectroscopic probe (ion evolution of magnetic helicity; temperature and fl ows), and arrays of • Determine the circumstances under magnetic probes (spatial profi les of the which 3-D effects dominate; local magnetic fi eld vector). The Sweet-Parker model of magnet- • Identify the mechanisms by which ic reconnection is a resistive MHD mod- magnetic energy is effi ciently con- el that assumes a 2-D incompressible, verted to plasma kinetic and ther- steady-state plasma. It captures many of mal energy; the essential local features of the mag- • Explore the fruitful utilization of re- netic reconnection layer and predicts reconnection to fusion concepts, such connection rates faster than that of resis- as application to self-organized plas- tive diffusion, but still much slower than mas. those observed in solar fl ares. For nearly 50 years, the merits and shortcomings of These studies will contribute to the ad- this model have been debated. The fi rst vancement of plasma physics and fusion laboratory experiments on the Sweet- energy research and will directly impact Parker model were performed on MRX. the physics understanding of reconnec- Null-helicity experimental data indicat- tion in fusion plasmas, the solar atmo- ed a reconnection speed consistent with sphere, the earth’s magnetosphere, and a generalized Sweet-Parker model, which related astrophysical phenomena. includes the effects of plasma compressibility, fi nite pressure in the downstream Experimental Setup region of the fi eld lines, and nonclassical and Past Major Results plasma resistivity. The measured plasma Two plasma toroids with identical to- resistivity was found to be enhanced over roidal currents are formed using induc- the classical Coulomb-collision value by tive electric fi elds generated from two up to a factor of ten; this enhancement sets of coil windings. The two plasma is thought to play a crucial role in deter- toroids are then merged together by pro- mining the reconnection rate. These re-

25 sults suggest that the Sweet-Parker model troversial subject in the theoretical liter- with nonclassical resistivity may explain ature with some claiming that it is nec- the fast reconnection required to be con- essary to provide anomalous resistivity sistent with solar fl are observations. for fast reconnection, while others claim In MRX the precise profi le of the mag- that it is not essential and may even slow netic fi eld in the current sheet has been down the process. There have been very measured by a very high-resolution mag- few experimental studies of turbulence netic probe array. The measured magnet- in current sheets, and none have inves- ic profi les fi t very well the Harris solu- tigated fl uctuations in current sheets in tion, which was developed in 1962. This MHD plasmas where the ion gyroradi- agreement is remarkable since the Har- us is much smaller than the experimen- ris theory does not take into account the tal apparatus. electric fi elds and dissipation associated Previous measurements of the elec- with reconnection. The sheet thickness trostatic component of the lower-hybrid is found to be on the order of the ion drift instability (LHDI) resulted in the skin depth, which agrees with a gener- conclusion that it did not play a signif- alized Harris theory incorporating non- icant role in reconnection on MRX. Al- isothermal electron and ion temperatures though the LHDI was identifi ed at the and fi nite electric fi eld. Interestingly, the low-beta region of the current sheet, elec- same scaling has been observed both in trostatic fl uctuations did not correlate the magnetotail and the magnetopause of well with the reconnection process in the Earth’s magnetosphere. their temporal and spatial behavior. The Conversion of magnetic fi eld energy to fl uctuation amplitude was also found to plasma kinetic and thermal energy is a pri- be relatively insensitive to the collision- mary consequence of reconnection. This ality of the plasma, in contrast with the process is believed to play an important strong dependence of the anomalous re- role in coronal heating, solar fl ares, and sistivity on collisionality. acceleration of auroral jets in the magne- Recently found electromagnetic fl uc- tosphere. Ion heating during reconnec- tuations, however, do correlate well with tion has been studied on MRX. Using reconnection. Those measurements are an ion dynamics spectroscopy probe, lo- done using a Hodogram probe capable cal ion temperature and fl ows were mea- of measuring polarization based on all sured. An ion temperature increase dur- three spatial components of the fl uctuat- ing reconnection has been observed, and ing magnetic fi eld acquired at the same the ion heating mechanism is a subject of location with a frequency response up to current research. 40 MHz. Typical raw signals and spectrograms which display the fl uctuation Highlights of Recent Results power in the time frequency domain are Studies of Fluctuations shown in Figure 3. The fl uctuation am- in MRX Current Sheets plitude is similar for the three compo- Current sheets formed in MRX con- nents, and the spectrum is peaked near tain strong gradients in plasma density the lower-hybrid frequency (shown by and cross-fi eld currents, both of which the solid line in the spectral plots). The can drive unstable fl uctuations and result amplitude is highest during the time of in turbulence. The role of turbulence in reconnection (260-280 μs). The radial magnetic reconnection has been a con- spatial profi le measurements show that

26 3 42 I (kA) 2 p 38 1 (cm) Plasma 0 Distance Current (kA) 34 0.4 B B r r 10 0 -0.4 0 0.4 B B z z 10 0

-0.4 f(MHz) 0 0.4 B B θ θ 10

0 Spectral Frequency Field Fluctuations (V) Amplitude of Magnetic -0.4 0 250 260 270 280 250 260 270 280 Time (µsec) Time (µsec) Figure 3. Traces of typical raw signals during reconnection represented by plasma current (top left panel). Spectrograms are shown on the lower-right panels where ﬂ uctuations pow- ers are color coded (decreasing power by order of red, yellow, green, blue, and white) in the time-frequency domain. The black lines indicate lower-hybrid frequency. The top right panel displays locations of the probe (red line) and the current sheet (center as black solid line and edges as dashed lines). When the current sheet center moves close to the probe, high- frequency magnetic ﬂ uctuations are detected. Experimental parameters are: radius R = 37.5

cm, toroidal angle θ = 22.5°, gas = H2, ﬁ ll pressure = 2.6 mTorr, z = 0, and capacitor bank voltages = 12 kV and 10 kV.

the magnetic fl uctuation amplitude is [Figure 4(a)]. Since resistivity enhance- strongly peaked near the center of the ment also strongly depends on the plas- current profi le which is in sharp contrast ma collisionality, a clear positive corre- with the electrostatic fl uctuations. lation between magnetic fl uctuations in To identify the observed electromag- the lower-hybrid frequency range and re- netic waves, it is crucial to measure their sistivity enhancement is established in the propagation characteristics. The acquisi- low-collisionality regimes [Figure 4(b)]. tion of all three components of the fl uctu- ating magnetic fi eld permits a Hodogram Fine Magnetic Structure analysis. It is concluded that the observed in the MRX Current Sheet magnetic fl uctuations are right-hand po- An alternative scenario to explain fast larized, whistler-like waves propagating reconnection invokes non-MHD ef- obliquely to the magnetic fi eld. The mag- fects such as the Hall effect to modi- nitude of the wave vector is determined fy the structure of the reconnecting cur- using the phase shift between two spatial rent sheet. Recent numerical simulations points. It is found that magnetic fl uctua- show that the inclusion of the Hall term tions propagate mainly in the current di- into the generalized Ohm’s law speeds up rection along with electron drift. reconnection. When the current sheet It is found that the amplitude of mag- width becomes comparable to the ion netic fl uctuations is sensitive to plasma skin depth, the ions are no longer magne- density or, equivalently, collisionality tized and decouple from magnetic fi eld.

27 1.0 (a)10 (b) Spitzer η */ η (Gauss) z B δ

Fluctuations Noise Level

Amplitude of Magnetic Field 0.1 1 Anomalous Resistivity

0.1 1 10 0.1 1.0 Density n (1019m-3) Amplitude of Magnetic Field δ Fluctuations Bz (Gauss) Figure 4. Magnetic ﬂ uctuations amplitude versus density measured by Langmuir probe (a) and resistivity enhancement at the current sheet center (b). Experimental parameters are: radius R = 37.5 cm, toroidal angle θ = 22.5°, Time t = 266-276 μs.

On the other hand, electrons remain tion. By rotating the probe, the measured magnetized until they reach the inner component of the magnetic fi eld can be region, called the electron diffusion re- changed. gion, whose width is proportional to the One feature which is observed in high- electron skin depth. It is the decoupling ly collisional plasmas is the formation of the electrons and ions that makes the of a bifurcated current sheet. Figure 6 Hall term important. It has to be noted shows the radial profi le of the reconnect- that although this theory became quite ing magnetic fi eld measured by the fi ne popular in the recent years, there is no structure probe at six time points during convincing laboratory experimental data pull reconnection. As the current sheet to assure the importance of Hall effects begins to narrow, two dips are seen in the in driving fast reconnection. magnetic fi eld. Each dip can be modeled To probe the structure of the recon- as a separate Harris current sheet with its necting current sheet on a scale length comparable to the electron diffusion region, new diagnostics must be developed. One such diagnostic is the “fi ne structure” probe, which consists of a linear array of 71 variably spaced magnetic pick- up coils (Figure 5). In the center, the coils are spaced 1.25-mm apart, giving a spatial resolution comparable to the electron skin depth which is one to three mm in MRX. The signals from the coils are integrated in hardware and digitized at a rate of 2.5 MHz. This allows the mea- Figure 5. The new MRX fi ne-structure surement of the radial profi le of the mag- magnetic probe. The dime helps show the netic fi eld at high space and time resolu- relative size.

28 0.06 0.06 0.06 t = 260µs t = 264 µs t = 268 µs 0.04 0.04 0.04

0.02 0.02 0.02 (Tesla) (Tesla) (Tesla)

z z z 0 00 Field B Field B Field B -0.02 -0.02 -0.02 Reconnecting Magnetic Reconnecting Magnetic Reconnecting Magnetic -0.04 -0.04 -0.04 2832 36 4044 48 2832 36 4044 48 2832 36 4044 48 Major Radius (cm) Major Radius (cm) Major Radius (cm) 0.06 0.06 0.06 t = 272µs t = 276 µs t = 0.04 0.04 0.04 280 µs

0.02 0.02 0.02 (Tesla) (Tesla) (Tesla)

Figure 6. The time evolution of the reconnecting magnetic fi eld profi le as measured by the fi ne-structure probe and the derived current profi le (red) for the high-collisionality regime.

characteristic hyberbolic tangent magnet- ma density, but the two channels are so ic fi eld profi le. The dips in the magnetic wide in the low density regime that they fi eld profi le correspond to two separate overlap and appear to be a single current current channels (shown in red on Figure sheet. The merging behavior is robust 6). As reconnection continues, the two and occurs even when the driving force current channels are observed to merge for reconnection is removed by crowbar- together over a time scale of a few Alfvén ring the poloidal coil current. This has times to form a single current sheet. The the effect of holding the fl ux constant double-peaked current density structure and preventing fi eld lines from being is seen near the quadrupole null point as pulled toward the coils. The crowbar was well. However, this data is not enough to fi red many Alfvén times before current rule out an X-point-like structure, since sheet formation, and merging behavior the center of the X-point could be dis- was always observed. This indicates that placed away from the axis by the probe. the X point structure is unstable and will The double-peaked current sheet collapse to a single current sheet in a few shows a clear dependence on collision- Alfvén times. ality, occurring in discharges with high fi ll pressure and plasma density. Howev- Graduate Studies er, the Harris sheet width depends on the and Science Education ion skin depth. Therefore, it is possible The small size and rich plasma phys- that the double peak exists at low plas- ics of the MRX make it an ideal facility

29 to study basic science and to train grad- the role of non-MHD effects in the cur- uate students. Aleksey Kuritsyn (Prince- rent sheet. Study of the fi ne-scale mag- ton University) is presently complet- netic structures in the neutral sheet will ing his thesis on optical studies of the go on with the help of a high-resolution neutral sheet physics in the MRX. Yang fi ne-structure probe which is fully op- Ren (Princeton University) has be- erational now. A more systematic study gan his research on experimental stud- of magnetic fl uctuations in the current ies of the Hall term driven reconnec- sheet is planned, and any relationship tion. The MRX project also participates between these fl uctuations and the re- in the summer student programs such as connection rate or ion heating will be the U.S. Department of Energy Nation- the subject of future research. Advanced al Undergraduate Fellowship program. diagnostics will be brought to bear on Under this program during the summer these studies, including the use of pla- of 2003, the MRX project hosted Kevin nar laser-induced fl uorescence to obtain Dusling, from Cooper Union College in 2-D images of the ion density in MRX New York City, who studied the depen- current sheets. Further studies of the dence of the current sheet width on col- global MHD aspects of reconnection lisionality and boundary conditions for and investigation of the importance of different gases. boundary conditions and 3-D perturbations to the current sheet geometry are Future Work planned. The results from these efforts The search for the mechanism be- should bring us closer to understanding hind fast reconnection in MRX current the important process of magnetic re- sheets will continue in order to ascertain connection.

30 Theory and Advanced Simulations

he fusion energy sciences mission maintenance of the comprehensive set of of the Princeton Plasma Physics toroidal design and analysis codes. It has T Laboratory (PPPL) Theory De- advanced toward its mission goals by: partment is to help provide the scientif- ic foundations for establishing magnetic • Generating the physics knowledge confi nement fusion as an attractive, tech- required for the interpretation and nically feasible sustainable energy source. extrapolation of present experimen- Research advances described here high- tal results. light how improvements in understanding the basic mechanisms associated • Suggesting new approaches to stim- with magnetically confi ned plasmas have ulate experimental campaigns to im- helped enable signifi cant progress in the prove performance. fusion program during FY03. • Developing improved theoretical Continuing improvements in diag- analysis capabilities that are funda- nostic techniques together with exten- mentally sound. sions of experimental operating regimes in devices such as the National Spher- • Contributing to the innovative de- ical Torus Experiment (NSTX) have sign of new experimental devices. stimulated more realistic comparisons of experimental results with theoretical • Providing a stimulating research en- models. The resultant improvements in vironment that effectively enables the fi delity of the physics-based models the Laboratory to attract, train, and should help accelerate the pace of tech- retain the young talent essential for nical advances. In particular, the theo- the scientifi c excellence of the plas- ry activities have positively impacted ma sciences. the interpretation of results from experimental facilities such as the NSTX and As it moves forward, the PPPL Theo- have played a major role in the effi cient ry Department can be expected to con- and reliable design of attractive new fa- tinue to introduce innovative ideas, to cilities such as the National Compact make advances in analytical capabilities, Stellarator Experiment. and to provide validation and active ap- During the course of the past year, the plications of the best existing theoretical PPPL Theory Department has continued tools for interpretation and design. Con- to add to its internationally appreciat- tributions to the areas highlighted below ed contributions of seminal concepts, as illustrate the impact of theory on the fu- well as to its innovative development and sion program.

31 MHD Studies tion would occur, effectively clamping it in Toroidal Systems at zero before it could become negative. Advances in the area of magnetohy- This phenomena was called the “axisym- drodynamic (MHD) studies in toroidal metric sawtooth.” systems during the past year have fea- However, with a plasma beta as low as tured progress in: (i) improved under- 1%, the simulations using the “standard” standing of the effects of plasma pres- resistive MHD model show that this ax- sure on the “current hole” phenomenon isymmetric sawtooth mode can saturate observed in tokamaks and spherical tori due to pressure peaking in the island, (ST’s); (ii) the ability to realistically sim- which makes complete reconnection en- ulate energetic particle dynamics in ST’s ergetically unfavorable. This behavior such as NSTX; and (iii) realistic model- persists both in the MHD model and in ing of feedback stabilization of resistive a more complete plasma model in which wall modes in tokamaks. the plasma ions are represented as a collection of particles obeying the kinetic Effects of Plasma Pressure on the equations. Current Hole in Tokamaks and In contrast, when “two-fl uid” (i.e., Spherical Tori electrons and ions treated as separate but The multilevel physics, parallel pro- interacting fl uids) effects are retained in cessing plasma simulation code M3D the simulation model, the reconnect- has been used to study the current hole ing plasma begins to spontaneously ro- phenomena in tokamaks and ST’s in the tate (Figure 1). This rotation breaks the presence of plasma pressure and rotation. symmetry, allowing the complete recon- It was previously reported that at low nection to occur, even at relatively large beta (ratio of plasma pressure to magnet- values of the plasma beta. Extensive sim- ic fi eld pressure), if the current in the cen- ulation studies have shown this two-fl u- ter of the torus were forced to decrease id induced rotation to be a robust effect, through magnetic induction, a reconnec- leading to repeated, successive axisym-

Figure 1. Two-ﬂ uid effects cause the axisymmetric island to rotate, breaking the symmetry and allowing reconnection.

32 metric sawtooth crashes for virtually all more realistic anisotropic distribution, experimentally relevant values of plasma the dominant linear n = 2 mode has a pressure. signifi cantly lower frequency, as compared to the TAE’s frequency. This is also Hybrid Simulations of Energetic in agreement with the experimental re- Particle Modes in a Spherical Torus sults, where low-frequency modes simi- Recent NSTX results show rich beam- lar to the “fi shbone” mode were observed driven Alfvén instabilities in neutral- in addition to TAEs. In the nonlinear re- beam-heated plasmas. The M3D code gime, the M3D simulations show that was applied to simulate the beam-ion- the n = 2 mode’s frequency chirps down driven Alfvén instabilities in NSTX. as it moves out radially (Figure 2). Ini- The M3D code is a multi-level extend- tial nonlinear simulations with multiple ed MHD code which treats the thermal modes show similar behavior. species as a single fl uid or as two fl uids and treats energetic ions as drift-kinet- Feedback Stabilization of the ic or gyrokinetic particles. Recent exten- Resistive Wall Mode in Tokamaks sion of the M3D hybrid code to gener- The model of the feedback stabiliza- al three-dimensional (3-D) geometry and tion of resistive wall modes (RWM) in to massively parallel platforms makes this tokamaks has now progressed to incor- calculation possible. In the linear regime porate feedback coils internal to the resis- with an isotropic beam ion distribution, tive vacuum vessel (I-coils) in accordance the M3D simulation results show unsta- with the corresponding modifi cation of ble Toroidal Alfvén Eigenmodes (TAEs) the DIII-D device at General Atomics. with frequencies consistent with exper- These new coils add much more fl exibil- imental observations in NSTX. For a ity to the feedback capabilities, but at the

Figure 2. Linear (left) and nonlinear (right) mode structure of n = 2 Toroidal Alfvén Eigen- mode mode.

33 same time add more complexity to the models the experiment. A relative phase analysis. Whereas the external mid-plane shift of roughly 2π/3 between the coils is coil (C-coil) current path of the previ- seen in the model and also experimental- ous confi guration was designed primarily ly. The relative currents in the coils also to sustain the stabilizing eddy current in agree. the shell, the new coils can be tailored to affect the MHD modes more effi ciently Turbulence and Transport with appropriate relative phasing of the Studies: Theoretical Analysis coils. The previous analysis using a nor- and Gyrokinetic Simulations mal mode approach with the DCON- Over the past year, advances in turbu- VACUUM codes has been extended for lence and transport studies in toroidal this study. systems have featured progress in: (i) the Figure 3 shows the calculated shell cur- ability to realistically simulate the neo- rent distributions of the unstable RWM classical properties for general geometry and the two least stable modes of the in toroidal plasmas and (ii) cross-code open loop system, noting the differing validation of trends observed in massive- helicities of the confi gurations. The up- ly parallelized full torus gyrokinetic parti- per and lower I-coils must be phased to cle simulations of microturbulence; match the RWM. The feedback modeling has been per- Comprehensive Simulations formed for a range of normalized beta and of Neoclassical Transport other equilibrium parameters. The opti- in Toroidal Plasmas mal phase shifts of the sensor loops, and Neoclassical transport is routinely of the upper and lower I-coils, relative to compared with experimental results. In the C-coil for stabilizing the RWM have assessing the confi nement properties of been calculated. It is found that the rela- toroidal plasma, it is important to accu- tive effectiveness of the I-coils is about 3- rately calculate the neoclassical dynamics 4 times that of the C-coils as judged by which set the irreducible minimum lev- the ratios of the energizing currents and el of transport in such systems. A glob- sensor signals. This simulation closely al particle-in-cell (PIC) code, GTC-Neo,

(a) (b) (c)

1.0 1.0 1.0 θ 0.5 0.5 0.5

0 0 0 0 0.5 1.0 0 0.5 1.0 0 0.5 1.0 φ φ φ

Figure 3. The current distributions on the (φ, θ) plane of the resistive shell of the three least stable open loop (i.e., with feedback turned off) eigenfunctions. Only the one shown on the left is unstable. Typically the code uses about 40 eigenmodes. The phase of the unstable mode matches the phases of the feedback coils.

34 has been developed to systematically study neoclassical physics and equilibri- 10 um electric fi eld dynamics of realistic toroidal plasmas. The associated simulation model incorporates the comprehensive infl uence of general geometry, fi nite ion orbit width effects, a self-consistent am- 1

bipolar electric fi eld, plasma rotation, Normalized Heat Flux and an accurate model to represent like- 0 0.2 0.4 0.6 0.8 1 particle collisions. r / a This newly developed computational Figure 4. Normalized heat fl ux from GTC- capability allows us to assess the irreduc- Neo simulations (dashed curves) compared ible minimum transport level, bootstrap to standard (Chang-Hinton) neoclassi- current, and large-scale radial electric cal estimates (solid curves) for large (black fi eld of a real machine for experimen- curves) and fl at (orange curves) temperature gradient (in inner region only) cases in tal comparison, directly using the three a NSTX plasma. measured plasma profi les: density, temperature, and toroidal rotation angular velocity. The code has been rigorously a NSTX plasma. In both the large and benchmarked against neoclassical theo- fl at temperature gradient cases, the actual ry in the limit of large aspect ratio with values for the ion heat fl ux are almost the small orbit size. It has been used to study same, indicating an overall global (nonlo- the interesting fi nite orbit physics of neo- cal) trend. It is also shown that large ion classical transport associated with non- temperature gradient can increase the standard orbit topology near the magnet- bootstrap current; but a steep density ic axis and with steep plasma profi les. gradient does little. When plasma rota- Applications to shaped plasmas, in- tion is taken into account, the rotation cluding those for NSTX and DIII-D, gradient can drive additional bootstrap found that the ion thermal transport ex- current either positive or negative, de- hibits a nonlocal and nondiffusive char- pending on the gradient direction. How- acter in the region close to the magnetic ever, for typical experimental situations, axis. Specifi cally, the ion heat fl ux is al- this change of bootstrap current is found most constant, independent of the value to be insignifi cant (less than 20%). The of the local temperature gradient. Com- largest modifi cation of bootstrap current pared to standard neoclassical theory (lo- is found near the magnetic axis. Typical- cal transport picture), the ion heat trans- ly, at r/a = 0.05 it is about two times the port calculated here can be much lower value from neoclassical theory estimates. than the neoclassical level in the presence of a signifi cant temperature gradient. Full Torus Gyrokinetic Particle This basically verifi es earlier simulation Simulations of Microturbulence results. However, for relatively fl at tem- Massively parallelized full torus gyroki- perature profi les, the ion heat fl ux ob- netic particle simulations have been car- tained from GTC-Neo can be close to or ried out for large-scale device-size scans even much larger than the usual theoreti- and successfully benchmarked both lin- cal prediction. Figure 4 shows this nonlo- early and nonlinearly against fl ux-tube cal picture of ion thermal transport for (local) gyrokinetic results. These valida-

35 tion studies support previously reported work on a simple dynamical theory and important results addressing the critical comprehensive diagnostics of the simu- question of transport with respect to de- lation results in collaboration with the vice size for toroidal plasmas. These were University of California, Irvine, and the obtained from applications of the three- University of California, San Diego. It is dimensional particle-in-cell gyrokinetic shown that while the transport driven by toroidal code (GTC) in general geometry microscopic fl uctuations (with a radial and made effi cient use of the full com- correlation length on the order of sever- puting power available from the IBM-SP al ion gyroradii) is diffusive, the transport massively parallel computer at the Na- scaling can deviate from the gyro-Bohm tional Energy Research Supercomputer scaling since the fl uctuation intensity in Center (NERSC). The GTC code is the the linearly unstable zone can be reduced representative of the Fusion Energy Sci- by nonlocal effects caused by turbulence ences Program in the NERSC bench- spreading into the linearly stable zone. As mark suite of codes which will be test- shown in Figure 5, the radial profi le of ed on the most advanced computational the ion thermal diffusivity is remarkably platforms such as Japan’s Earth Simula- close to that of the fl uctuation intensity. tor Computer, the world’s fastest super- As the system size gets smaller, the extent computer. of radial spreading of turbulence into the The GTC code can presently run on linearly stable zone gets wider relative to the IBM SP at NERSC with more than the system size, allowing deviation from 2,000 processors with excellent parallel gyro-Bohm scaling of transport. It scales effi ciency. Simulation results from GTC with the gyroradius ~25ρi, while the sim- have also been complemented by the ple analytic theory predicts ~18ρi. development of a nonlinear theoretical model which shows that nonlocal phys- Theoretical Studies ics associated with turbulence spreading of Energetic Particle Physics into the linearly stable region can cause In view of the increased interest in the gradual transport scaling change from burning plasma physics properties in de- Bohm to gyro-Bohm observed in the vices such as ITER, advances in energet- simulations. For the relevant parameters studied, this critical transition occurs as

3.2 )

40 i

the minor radius exceeds around 400 ion χ ρ ( gyroradii. To help enable the implemen- a=500 i tation of more complete physics in these 30 2.4 simulations, the feasibility of the electro- 20 ρ 1.6 static split-weight scheme with trapped a=250 i electrons in toroidal geometry has been 10 a=125ρ 0.8 demonstrated using an algebraic multi- i Fluctuation Intensity ( I ) grid solver. 0 0 Ion Thermal Diffusivity 0 0.2 0.4 0.6 0.8 1.0 Deeper physical understanding of the r/a size scaling of transport results from the Figure 5. Fluctuation intensity proﬁ les (I in previous massively parallel global gyroki- solid lines) and ion thermal diffusivity (χi netic particle simulation of ion tempera- in dashed lines), both in gyro-Bohm units, ture gradient (ITG) turbulence using the after nonlinear saturation for a = 125ρi, GTC code has been gained by analytic 250ρi, and 500ρi.

36 ic particle studies in toroidal systems are were observed with n = 1-2 (n is the to- particularly timely. Research on this top- roidal mode number), whereas in DIII-D ic over the past year has featured prog- n = 2-7. The confi rmation of the n-scal- ress in: (i) providing a viable explanation ing helped to validate the predictive capa- of fast-particle-driven Alfvénic instabili- bilities of the NOVA-K code for studying ties in higher beta toroidal plasma such ITER plasmas. The analysis predicts that as produced in NSTX; (ii) simulations the main damping mechanisms are radi- of Alfvén instabilities in ITER, and (iii) ative processes and ion Landau damping, high sub-ion cyclotron frequency insta- which can be balanced against the desta- bilities in toroidal plasmas. bilizing effects from the beam ion pressure gradient in determining the stability Low-frequency Alfvénic threshold of the TAE modes. Instabilities in Toroidal Plasmas Alfvénic instabilities driven by the Simulations of Alfvén neutral-beam-injected (NBI) fast ions Instabilities in ITER in NSTX plasmas have been observed. To study TAE stability in ITER plas- A low-fi eld, low aspect-ratio device such mas, the nonperturbative, fully kinet- as NSTX is an excellent testbed to study ic HINST code for shorter wavelength the ITER-relevant burning plasma phys- (medium to high toroidal mode number) ics of fast particle confi nement. The low modes and the global NOVA/NOVA-K Alfvén speed in NSTX offers a window hybrid ideal-MHD/kinetic codes for lon- in the super-Alfvénic regime expected in ger wavelengths (low to medium toroidal ITER (“The Way” in Latin). Effects such mode number) modes were employed. as large fi nite Larmor radius, orbit width, From the HINST code calculations, the plasma shaping and high thermal and fast- TAE growth rate due to alpha particles is ion betas make this effort a greater chal- found to be on the order of a few percent lenge. Low-frequency MHD activities, of the real frequency, in agreement with ~100 kHz on NSTX, are often observed the global NOVA-K calculations. How- and identifi ed as the toroidicity-induced ever, due to the global TAE mode struc- Alfvén Eigenmodes (TAE’s) driven by ture, NOVA-K usually predicts more sta- NBI ions. They are often accompanied by ble modes than HINST. beam ion losses (up to 15% neutron signal Application of the NOVA/NOVA-K drop) in high-confi nement-mode plasmas codes to ITER plasmas shows an unsta- with high safety factor at the magnetic ble domain of TAEs with toroidal mode axis. The numerical analysis of TAE sta- numbers spanning 8 < n < 20. The pro- bility using the NOVA-K code has shown posed 1-MeV negative neutral-beam ions good agreement with the observed TAE can contribute as much to the instabil- data. Furthermore, by creating very sim- ity drive as the fusion alphas. However, ilar plasma conditions on NSTX and the if the beam injection energy is lowered DIII-D tokamak, similarity experiments to 500 keV, TAEs can be stabilized. The

were designed to verify the theoretical background plasma temperature of Ti0 = predictions that the toroidal mode num- 20 keV appears to be the threshold for

ber of the most unstable TAEs scales with stable plasma operations, and with Ti0 > the machine size. The NOVA-K analysis 20 keV, TAEs will be unstable. Figure 6 subsequently validated these similarity ex- shows the dependence of the ratio of the periments. In particular, the NSTX TAE’s driving term to the total damping of the

37 4 The GAE is radially localized near the α−particles only minimum of the Alfvén continuum and α−particles and 1MeV NNBI 3 is dominated by a single poloidal harmonic. Due to tangential neutral-beam injec- damp Unstable γ

/ tion in NSTX, the distribution function 2 of beam ions has a positive gradient in the +NNBI α ,

α velocity space and forms a “bump on tail” γ 1 in the velocity space direction perpen- Stable dicular to the magnetic fi eld, which pro- 0 vides the energy source for the instability 51015 Toroidal Mode Number (n) to develop. When beam ions are in Dop- pler-shifted cyclotron resonance with the Figure 6. Predicted linear Toroidal Alfvén modes, GAE’s are unstable if beam ions Eigenmode stability in ITER. More than ten toroidal mode numbers could be unsta- are strongly super-Alfvénic, as in the case ble. of NSTX plasmas. Three-dimensional hybrid simulations using the HYM code TAE. The curve with stars represents the have been employed to study the excita- case when only alphas are included in the tion of these higher-frequency Alfvén ei- driving term, whereas the curve with “x” genmodes by energetic ions in NSTX. points corresponds to the case when both The HYM code is a nonlinear, global alphas and beam ions are included in the stability code in toroidal geometry, which driving term. includes a fully kinetic ion description. High Sub-ion Cyclotron Frequen- Beam ions are treated with full orbits cy Instabilities in Toroidal Plasmas. In with the delta-f method, while the back- the high-frequency range of Alfvén insta- ground plasma is treated with the one- bilities, recent observations of rich sub- fl uid resistive MHD model. The dynam- ion cyclotron frequency MHD activity ics of these two plasma components are in NSTX plasmas suggested an addition- coupled via a current coupling scheme. al new instability, which is identifi ed as The effects of the beam ion toroidal and the Global Alfvén Eigenmode (GAE). poloidal currents are included nonper- Similar to the Compressional Alfvén Ei- turbatively to account for the anisotro- genmodes (CAEs), the GAEs are desta- pic fast-ion pressure tensor and to cal- bilized by the Doppler-shifted cyclotron culate self-consistent equilibria, which resonance in the presence of 80-keV NBI serve as an initial condition for the 3-D ions. To simulate GAE/CAEs in realis- simulations. HYM simulations for typi- tic NSTX plasma conditions, an analytical NSTX parameters confi rm that, for cal theory and a nonlinear hybrid kinet- large injection velocities of beam ions ic-MHD code, HYM, which is capable and strong anisotropy in the pitch-an- of computing the mode structure, satura- gle distribution, there are unstable high- tion, and energetic particle transport has frequency Alfvén modes. It is found that been developed. The theory predicts that the most unstable modes with low toroi- GAEs are formed with frequencies below dal mode numbers, 2 < n < 7, are GAE the minimum of the Alfvén continuum, modes. These modes are found to be lo- and that the eigenmode frequency is de- calized near the magnetic axis, and have termined by the product of the Alfvén large parallel wavenumbers to satisfy the velocity and the parallel wavenumber. dispersion relation. The computed poloi-

38 dal velocity has a vortex-like structure, oped. Visualizations of the information which is characteristic for shear Alfvén input to and output from DEGAS 2 have waves. However, in NSTX these modes provided a better understanding of the have a signiﬁ cant compressional compo- spatial relationships of the physical ob- nent, due to strong coupling to the com- jects in the experiment. Direct compar- pressional Alfvén wave. isons of the experimental and simulated GPI camera images allow the consistency Plasma Boundary Physics of the available diagnostic data to be as- The objective of the NSTX “gas puff sessed, as shown in Figure 8. The neutral imaging” (GPI) experiments is to pro- density computed by DEGAS 2 in sim- vide high spatial and temporal resolu- ulations validated in this way can then tion data on edge plasma turbulence. be used in other GPI-related studies. For While the geometry of the diagnostic is example, J. Myra and D. D’Ippolito of designed to optimize the quality of those Lodestar Research have developed a pro- data, the three-dimensional nature of the cedure utilizing the DEGAS 2 neutral experimental conﬁ guration complicates density that allows the time-dependent, interpretation and utilization of the re- turbulent plasma parameters underlying sults, as illustrated in Figure 7. As a re- the GPI emission to be inferred. These sult, 3-D simulations of the GPI experi- plasma data are being used to test theo- ments with the DEGAS 2 Monte Carlo ries of the evolution of edge plasma tur- neutral transport code have been devel- bulence.

587.6 nm Neutral Helium Emission Density Isosurface Cloud

Helium Density Contour Outlines Simulated Manifold

Field-line-following Electron Density Perturbation

Electron Density Contours on Z = Constant and Corners of Y = Constant Planes Camera View

Figure 7. Visualization of the three-dimensional DEGAS 2 code gas puff imaging simulation.

39 Discharge 108311 Discharge 108322 High-confinement mode Low-confinement mode 160 160

Z R 120 120

80 80 Vertical Pixel Vertical Vertical Pixel Vertical

40 40

0 0 04080 04080 Horizontal Pixel separatrix Horizontal Pixel

004.6x1019 9.1x1019 4.5x1019 9.1x1019 Emission Rate (photons / m2 s st) Emission Rate (photons / m2 s st) Figure 8. Comparisons of simulated (color images) and experimental (line contours) gas puff imaging emission clouds.

The DEGAS 2 gas puff imaging simu- Theory Support for the NSTX lations have been made possible by contin- The PPPL Theory Department con- ued improvements in the code. The abili- tinued to play a major role in the analy- ty to treat toroidally segmented problems sis and modeling of NSTX in the topical was added to the DEGAS 2 geometry areas of MHD, transport and turbulence, setup code, 3-D extensions to the specifi - boundary physics, and the interactions of cation of neutral sources were added, and energetic particles with MHD. 3-D graphics were developed. The geom- Understanding the effect of the ob- etry setup code was subsequently modi- served rapid rotation in NSTX plasma on fi ed to handle 3-D objects consisting of MHD equilibrium and stability is an on- two-dimensional (2-D) shapes rotated going topic of research. In collaboration through a limited range of toroidal angle. with the University of Rochester in New A new set of helium atomic physics data York equilibrium modeling with fl ow has also been obtained and adapted for shows density asymmetries comparable use in DEGAS 2. These data are the re- to the observations, as rotation shifts par- sult of a state-of-the-art model developed ticles off fl ux surfaces. The high velocities by M. Goto of Japan’s National Institute also contribute to reduced-mode growth for Fusion Science. rates. A new observation from the simu-

40 lations of sawtooth reconnection is, that observations of a sub-ion cyclotron fre- in addition to the fl attening of the pres- quency range instability in NSTX have sure profi le, the toroidal velocity profi le also motivated theory developments. is also fl attened inside the island. This re- The instability is found to be driven by sult is consistent with the limited experi- beam ions in the positive gradient re- mental data available. gion of the beam distribution function in As described above in the Turbulence velocity space. These ions excite a cavi- and Transport Studies section, a global ty mode, which is identifi ed as a global particle-in-cell code, GTC-Neo, has been shear Alfvén eigenmode. The predicted developed to systematically study neo- mode dispersion is consistent with exper- classical physics and equilibrium electric imental observations. fi eld dynamics of realistic toroidal plas- Progress has also been made in the sim- mas. The simulation model incorporates ulation of sub-cyclotron frequency modes the comprehensive infl uence of: general driven by the energetic neutral beam ions geometry, fi nite ion orbit width effects, in NSTX, using the HYM code. Hybrid a self-consistent ambipolar electric fi eld, MHD/delta-f particle simulations show and an accurate model to represent like- the excitation of Global Alfvén Eigen- particle collisions. Application of GTC- modes (GAE), which are the most un- Neo to NSTX using an equilibrium repre- stable modes at low n (2 < n < 7) with senting an NSTX discharge has produced growth rates of the order of 1% of the cy- an interesting physics trend. Specifi cally, clotron frequency (Figure 9). For each to- the ion thermal transport is found to ex- roidal mode number, several (dominant) hibit a nonlocal and nondiffusive char- poloidal modes are unstable. Simulations acter in the region close to the magnetic for n > 7 show edge-localized modes with axis due to nonstandard orbit topology, a a large compressional component (CAE). feature characteristic of spherical tori. CAE modes have smaller growth rates Gas puff imaging experiments on ~0.001-0.003 of the cyclotron frequen- NSTX provide an interesting challenge cy, and larger poloidal mode numbers (m to theory and modeling. The DEGAS 2 ~ 8-10). Monte Carlo neutral transport code has been used to simulate helium atom behavior in these experiments on NSTX. These detailed simulations permit direct comparison of the code output with the images obtained from the GPI camera. Furthermore, visualizations of the information input to and output from DEGAS 2 have provided a better understanding of the spatial relationships of the physical objects in the experiment. Figure 9. Results from HYM code simula- Additional detail on this work is provid- tions. Time evolution of spectrum of unsta- ed above in the Plasma Boundary Phys- ble modes for toroidal mode number n = 4. ics section. Lower-frequency modes are Global Alfvén As noted in the highlights of progress Eigenmodes with poloidal mode numbers in the energetic particles studies area, new m = -2 and m = -3.

41 Stellarator Theory plied to edge modeling on NCSX by col- The PPPL Theory Department contin- laborators at Livermore. ued to have a critical lead role in address- The PIES collaboration with the Span- ing and resolving physics issues relating ish TJ-II group, which has been in abey- to the design of the National Compact ance for several years, was revived this Stellarator Experiment (NCSX). As the year. The most recent version of the PIES NCSX Project moves forward to its con- code was ported to Spain for use in the struction phase, work in the theory group analysis of TJ-II data. is turning to new studies motivated by the The NCSX fi eld error calculations long-term needs of the NCSX program, have been done with the PIES code to and to further adaptation and application benchmark the results of quasi-analyt- of tokamak tools and expertise to stellar- ic estimates of fi eld error tolerances and ators. In particular, the stellarator capa- show a signifi cant reduction in fi eld error bilities of the PIES and M3D codes have magnitude due to self-consistent plasma been further upgraded this year, and the effects not included in the quasi-analyt- codes have been applied to several phys- ic estimates. ics and modeling issues. A new tool has been developed for studying ballooning M3D Code Calculations stability, and a new equilibrium recon- The two-fl uid plasma model in the struction code has been created. M3D code has been applied to study limits on stellarator high-beta steady states, PIES Code Applications with emphasis on NCSX. Two-fl uid ef- and Development fects are found to fundamentally change The PIES code is being used to study the fast, MHD-time-scale quasi-steady fl ux surface issues in the W7-AS stellar- states, compared to MHD. They effec- ator in Germany, and the results of cal- tively stabilize the high-mode-number culations thus far correlate well with the resistive ballooning/interchange modes attainable betas in W7-AS experiments. that limit beta in MHD for fi xed plas- For the purposes of this study a modifi ed ma boundaries, well above the MHD version of the PIES code was produced, limit (7-8% beta compared to 4%, for allowing the specifi cation of a fi xed, ex- NCSX). The two-fl uid terms produce perimentally determined pressure profi le some effects similar to those of the neo- and applying an appropriate model for classical parallel viscous stress. They drive the pressure-driven current in stochas- a steady-state radial electric fi eld similar tic regions. The modifi ed code has been to the neoclassical electric fi eld driven at applied to a series of experiments which low collisionality. A rapid increase in is- studied the infl uence of control coil cur- land growth with beta, at higher beta, rent on the attainable beta. suggests that one stellarator beta limit is A new package has been developed for determined by deteriorating plasma con- the free-boundary version of the PIES fi nement due to large magnetic islands, code that allows the code to use a diver- rather than intrinsic turbulence or cata- tor-like boundary condition, in addition strophic instability. to the limiter boundary condition previously used. Primarily, German collabora- New Code Development tors at Greifswald have done this work. A new computational tool for study- The new version of the code is being ap- ing the ballooning stability properties of

42 stellarator equilibria has seen continued ria from emissivity data. The code pres- development. By perturbing the pressure ently operates on 2-D equilibria, and the gradient and shear at a selected surface, 3-D features of the code are now being marginal stability diagrams for balloon- debugged. ing modes are constructed for stellarators that are analogous to the diagrams constructed for tokamaks in terms of the Field-Reversed magnetic shear (s) and pressure gradient Confi guration Stability Studies (α) parameters. This method shows that, Stability properties of fi eld-reversed in particular, an increasing pressure gra- confi gurations (FRCs) have been studied dient alters the local shear. This effect using the 3-D nonlinear hybrid and mag- leads to the phenomenon of second-sta- netohydrodynamic (MHD) simulation bility in both tokamaks and stellarators. code HYM. A new parallelized version of Results from this procedure are illustrat- the HYM code has been developed using ed in Figure 10. 3-D domain decomposition. In addition, A new 3-D equilibrium reconstruction single-processor optimization has been code is also being developed. An earlier completed, and the data layout and struc- formal result, generalizing a 2-D meth- ture of the HYM code has been modifi ed od of Christiansen and Taylor to 3-D using modern Fortran-90 language fea- systems such as stellarators, is now being tures to improve in-cache performance implemented in a code, to test whether and portability and maintainability of the method can be used as a novel diag- the code. Both the MHD and the delta-f nostic for stellarators, allowing practical particle versions of the HYM code have reconstruction of 3-D stellarator equilib- been parallelized. Flexibility of the model allows use of independent 1-D to 3-D domain decomposition of the particle grid and the fi eld grid to achieve the best parallel performance and load balanc- ing for various problem sizes and differ- -100 100 ent applications. For a prescribed, small- size problem, very good parallel scaling has been obtained for up to 30 processors. The HYM code has been ported to the NERSC IBM SP computer. Recent accomplishments include: (a) -100 100 study of the effects of fi nite electron pressure on FRC stability properties; (b) initial 3-D MHD simulations of counter- helicity spheromak merging and FRC formation in support of the SSX-FRC experiment at Swarthmore College; (c) -100 100 development of a new parallelized Grad- Figure 10. Local magnetic shear on a fl ux Shafranov equilibrium solver FRCIN, surface for three confi gurations similar to which allows calculation of self-consis- the NCSX design, with varying pressure tent kinetic equilibria for arbitrary ion gradient. distribution functions; (d) nonlinear

43 study of the evolution of the tilt mode mentally relevant FRC equilibria, it satu- in FRC confi gurations with different val- rates nonlinearly without destroying the ues of the elongation and the FRC kinet- confi guration, provided the FRC kinetic _ ic parameter s, which measures the num- parameter is suffi ciently small. The satu- ber of ion gyroradii in the confi guration. ration of the n = 1 tilt instability occurs It has been demonstrated that, contrary in the presence of ion toroidal rotation, to the usually assumed stochasticity of and is accompanied by the growth of n the ion orbits in the FRC, a large fraction ≥ 2 rotational instabilities (Figure 12), of the orbits are regular in long kinetic which are often seen in experiments. The confi gurations. A stochasticity condition saturation of the n = 1 tilt instability oc- is found (Figure 11), and the number of curs due to the nonlinear change in the _ regular orbits is shown to scale as 1/s. ion distribution function, and the stabi- The nonlinear evolution of MHD in- lizing effects of ion sheared rotation and stabilities has been studied for a wide the nonlinear interaction with growing _ _ range of s values. The linear and nonlin- n ≥ 2 rotational modes. Large-s simula- ear stability of MHD modes with toroi- tions show no saturation of the tilt mode, dal mode numbers n ≥ 1 has been investi- and there is a slow nonlinear evolution of gated, including the effects of ion spin-up the instability after the initial fast linear and fi nite electron pressure. A modifi ed growth. Overall, the hybrid simulations delta-f scheme has been developed that demonstrate the importance of nonlinear allows switching dynamically from the effects, which are responsible for the sat- _ delta-f method to the conventional (i.e., uration of instabilities in low-s confi gu- full-f) particle-in-cell method, as the per- rations, and also for the increase in FRC turbation amplitude becomes large. The lifetime compared to MHD models in _ results of nonlinear hybrid simulations of- high-s confi gurations. fer a defi nitive explanation of the stability _ properties observed in low-s FRC experi- Fusion Energy Science ments. It has been demonstrated that, al- Pilot Computing Facility though the n = 1 tilt mode is linearly the The PPPL pilot Fusion Computation- most unstable mode for nearly all experi- al Center (FCC) began operation during FY03. This jointly funded Fusion Ener- gy Science (FES) facility was established with resources from the Department of 1.0 Energy (DOE) and Princeton Universi- pφ ty, including the University’s Princeton |ψ | 0 0 Institute for Computational Science and Engineering (PICSciE). Complementa- ry to its involvement in “capability com- -1.0 puting” activities on the most powerful 1234 ε available supercomputing platforms at major centers (e.g., at the National Ener- Figure 11. Scatter plot of the particle distri- gy Research Scientifi c Computing Cen- bution in (ε, pφ) phase space. Color is used to mark the regular-orbit (green) and ergo- ter (NERSC) and at Oak Ridge National dic-orbit (red) particles. The solid line cor- Laboratory), the FCC addresses impor- responds to the analytical stochasticity con- tant “capacity computing” issues by ex- dition. amining the cost-effective utilization of

44 n) fi le exchange, but direct common access δ 0.03 (a) to computers, software, data, and other n=2 resources. In general, knowledge gained 0.02 through this pilot project about capabil- n=1 ity as well as capacity computing issues 0.01 n=3 can be usefully applied toward planning future FES investments in computational 0 n=4 infrastructure. Nevertheless, the main ra- Density Perturbation ( 0 20 40 60 80 tionale behind the creation of the PPPL Time in Units of the Alfvén Time (t/tA) Fusion Computational Center was, and (b) still is, to provide to the fusion community a dedicated system based on capacity computing. As NERSC moved towards a policy that favors large simulations from codes that can scale to more than 1,000 processors, it makes the FCC even more t = 60tA t = 76tA relevant, if not essential. NERSC is now, Figure 12. Results from nonlinear HYM for the most part, a “capability comput- simulations of fi eld-reversed confi guration ing” center, handling the most challeng- plasmas: (a) Time evolution of the n = 0- ing calculations requiring extremely large 4 Fourier harmonics of the ion density per- resources. The FCC has proven to be an turbation and (b) contour plots of the per- invaluable tool for running smaller cal- turbed number density at the toroidal cross culations or some of the codes that use section at t = 60t and t = 76 , where A is A A a signifi cantly smaller number of pro- the Alfvén time. cessors and do not require such large resources. This effectively helps relieve the commodity clusters dedicated to key FES NERSC supercomputer. applications. This impacts FES partic- As part of the FCC, a new 128-proces- ipation in the DOE Offi ce of Science’s sor PC cluster has been extensively used Scientifi c Discovery through Advanced in the past year. Transport studies involv- Computing (SciDAC) program in that ing applications of the GS2 microturbu- it involves collaborations with sever- lence code (from the SciDAC Plasma Mi- al SciDAC teams, including the Plasma croturbulence Project) have been carried Microturbulence Project, the Extended out almost daily on this cluster. The 64- MHD Project, and the Fusion Collabo- processor GS2 simulations run at com- ratory. In addition, the facility includes parable speed to the NERSC systems due the strong involvement of Princeton to the relatively low sensitivity of GS2 to University, which provided matching latency. The Gyrokinetic Toroidal Code funds, and the National Oceanic and At- (GTC) has also been run on this cluster mospheric Administration’s Geophysi- for smaller, but just as relevant, calcula- cal Fluid Dynamics Laboratory in “grid tions as the ones done on the NERSC computing” explorations. Grid com- system as illustrated in Figure 13. In sup- puting is a distributed computing infra- port of GTC, the Globus GRID soft- structure for advanced physics and engi- ware has been installed to take advantage neering applications involving large-scale of the parallel multi-streaming I/O soft- resource sharing. This includes not only ware developed at PPPL by its Computa-

45 Figure 13. Results of nonlinear GTC simulation showing breakup of convective-cell eddies by zonal fl ow, limiting turbulent transport. tional Plasma Physics Group. This soft- University’s Main Campus. By thread- ware solves the important and diffi cult ing and buffering the I/O layer, it was issue of data management on PC clusters found that GTC ran faster on this cluster without requiring an expensive data stor- when the data streaming techniques were age system directly attached to the com- used compared to writing out data locally pute nodes. Another aspect of the pilot on their cluster. The underlying transfer studies was to examine the effectiveness mechanism was Globus GridFTP, which of grid computing for data management was able to stream data across the Prince- for the larger codes in the FES portfo- ton microwave link at a rate of over 98 lio (such as the GTC code). In the ini- Mbs. These important new fi ndings were tial experiments, the GTC code was run highlighted at the national Supercom- on the grid-cluster located at Princeton puting 2003 Conference.

46 Computational Plasma Physics

he Princeton Plasma Physics metry into account. The time to solution Laboratory (PPPL) Com pu ta- for a M3D simulation is dominated by T tion al Plasma Physics Group the time it takes to solve 13 elliptic equa- (CPPG) continued in its role of advanc- tions each time step. These elliptic equa- ing and disseminating modern compu- tions can be categorized into three types tational methods throughout PPPL and that correspond to: a weak diagonally the fusion community. The accomplish- dominant matrix, a moderate diagonally ments described in the subsequent sec- dominant matrix, and a strong diagonal- tions include (1) improving the effi ciency ly dominant matrix. of the production high-end theory simu- Previously, there was no alternative lation codes M3D and GTC, (2) further to the Generalized Minimum Residual development and support of the trans- (GMRES) solution procedure for a gener- port analysis code TRANSP as a National al sparse matrix. However, by taking into Fusion Collaboratory service, (3) further account the underlying symmetric struc- enhancement and maintenance of the ture of the coeffi cient matrices, another, National Transport Code Collaboration more effi cient linear solver, Incomplete (NTCC) Modules Library, (4) develop- Cholesky Conjugate Gradient (ICCG), ing new advanced numerical techniques was able to be implemented. The effi cien- based on adaptive mesh refi nement and cy of a direct Gauss LU solver was eval- Gabor wave packets, and exploring their uated for comparison purposes. Figure 1 application to fusion problems, and (5) illustrates the time to solution for these providing a high-end visualization dis- three solver types for each of the three ma- play wall and developing practical meth- trix types typical of M3D. Note that less ods for viewing very large remote data time is better in these comparisons. It is sets. Details are given in the subsequent observed that ICCG (CG) greatly accel- sections. erates the solution process as compared to GMRES, especially for the weak diagonal- Improvements in Theory ly dominant matrix. In the weak diagonal- Simulation Codes ly dominant case, 4 to 44 times speedup Symmetric Solver in M3D was achieved when the matrix order rang- The coeffi cient matrices in the mas- es from about 10 to 10,000. For the mod- sively parallel extended MHD code, erate diagonally dominant case, there is a 4 M3D, have been reformed to take ad- to 24 times speedup. For the strong diago- vantage of their symmetric structures, nally dominant case, an average two times and this has allowed solution by a more speedup is observed. Converting to the effi cient linear solver that takes this sym- symmetric structure and using the ICCG

47 Weak Diagonally Moderate Diagonally Strong Diagonally Dominant Dominant Dominant 100 LU 10 GUMRES CG 0

0.10

0.01

0.001

0.0001

0.00001 10 100 1,000 10,000 10 100 1,000 10,000 10 100 1,000 10,000 Matrix Order Matrix Order Matrix Order Figure 1. The M3D linear equations are now being solved by a the ICCG method (CG) that takes advantage of the underlying symmetric structure and greatly reduces time to solution. algorithm has thus led to over a factor of With some modifi cations to adapt to two speedup in the M3D code. the vector structure, many of the same scientifi c codes that do not perform well GTC Optimization on super-scalar computers can reach up to The gyrokinetic microturbulence sim- 75% of peak performance on vector su- ulation code GTC has been ported to percomputers such as the NEC SX-6. The the Japanese-made NEC SX-6 vector purpose of the on-going study has been supercomputer as part of the National to evaluate the work and reward ratio in- Energy Research Supercomputer Center volved in vectorizing the GTC code on (NERSC) benchmark suite of codes for the latest parallel vector machines, such the evaluation of new systems. The NEC as the NEC SX-6 and also the U.S.-made SX-6 node is the building block of the CRAY-X1. This evaluation was initial- much larger and much publicized Earth ly carried out on the 8-CPU SX-6 locat- Simulator computer in Japan. The im- ed at the Arctic Region Supercomputing pressive performance achieved in 2002 Center (ARSC), and has since been ex- by the 5120-processor Earth Simulator tended to 64 CPUs at the Earth Simulator (35 Tfl ops on Linpack, 87% of peak) has center in Japan. Present performance re- revived the interest of computational sci- sults reveal that the GTC code runs more entists in vector processors. Although the than fi ve times faster per CPU on the theoretical peak performance of the su- SX-6 vector processor compared to the per-scalar processors (such as are available NERSC IBM Power 3 super-scalar pro- at NERSC) rivals their vector counter- cessor. More work is being done to further parts, most scientifi c codes cannot obtain improve this performance and to evaluate these speeds due to memory bandwidth performance on the new CRAY-X1 locat- and latency limitations, and typically ed at the Oak Ridge National Laboratory. run only at a few percent of peak perfor- To improve the data management for mance (less than 10%). GTC, Globus-based parallel streaming

48 I/O routines have been developed and tested for real simulations. By taking advantage of GRID technology and software, the large amount of data generated by GTC can now be transferred in parallel, while the calculation is performed, to the location where the data is analyzed. Furthermore, this method has very little impact on the simulation performance.

Transport Analysis Figure 2. Fiscal year 2003 TRANSP code Code Development run production statistics. CMOD = Alcator C-Mod tokamak at the Plasma Science and Signifi cant improvements to both Fusion Center, Massachusetts Institute of physics modeling and operational capa- Technology, Cambridge, Massachusetts; bilities were achieved in the widely used D3D = Doublet DIII-D tokamak at Gen- TRANSP experimental data-analysis eral Atomics in San Diego, California; code this year. JET = Joint European Torus in the United In operations, the transition to the Kingdom; MAST = Meg Amp Spherical FusionGrid TRANSP production system Torus at the Culham Laboratory, United was completed. This system automatical- Kingdom; NSTX = National Spherical ly responds to run requests from autho- Torus Experiment at the Princeton Plasma rized users anywhere in the world via the Physics Laboratory, Princeton, New Jersey. internet. More than 1,600 runs were gen- Fiscal years 2000-2002 production (under the old system) averaged 950 runs per year. erated in 2003 for numerous experiments (Figure 2). Because the actual compu- tations take place locally, PPPL experts Associated with each run listing are fur- can monitor the system and debug runs ther links to the run’s log fi les and graph- that encounter problems. There are now ical monitoring data. A new feature of 38 magnetic fusion energy research us- the system, utilizing PPPL’s “ElVis” sci- ers from seven institutions with electron- entifi c graphics package, allows user-se- ic FusionGrid Certifi cates and authoriza- lected data to be monitored in graphi- tion to produce TRANSP runs on PPPL cal displays that are dynamically updated compute servers. TRANSP is the fi rst op- “during execution,” giving early feedback erational compute service, http://www. on run results. Figure 3 illustrates the fusiongrid.org, of the National Fusion procedure from a user standpoint. Collaboratory SciDAC project. Another operational improvement to Remote TRANSP users employ client the code is the option to accept the plas- software tools to request runs from their ma geometry and fi elds (i.e., the MHD local computing systems so that they do equilibrium fi le) from a data source and not need to log on to PPPL machines hold these fi xed in time. This enables the directly. Users can track the progress of code to run faster, by removing the re- their runs via the TRANSP site web site quirement to recalculate the equilibrium http://w3.pppl.gov/TRANSP. This site and associated geometric information links to the General Atomics “FusionGrid time dependently. This mode of operation Monitor,” which gives a summary of sta- has been used as the basis for a prototype tus of active and recently completed runs. time-slice “between-shots” analysis capa-

49 Web Browser Monte Carlo ions used in NUBEAM simulations. NUBEAM now supports a neutral TRANSP webpage particle analyzer (NPA) simulator, which has been deployed to study data from GA Fusion Grid the National Spherical Torus Experiment Monitor (NSTX) (Figure 4). The toroidal location Choose run of neutral beams and NPA detectors are specifi ed so, for the fi rst time, the NPA simulator looks at charge-exchange neutral e-fl ux generated from the three-di- Log ElVis mensional beam-injected fast neutrals files Graphics in addition to the one-dimensional fl ux- (text) surface-averaged thermal background ...... neutrals. Multiple diagnostic channels ...... and neutral particle species are supported in the simulation. The radio-frequency ray-tracing codes CURRAY and GA- Figure 3. Web-accessible information on ex- TORAY were installed in TRANSP and ecuting TRANSP code runs. are undergoing validation. CURRAY was validated for certain regimes of high-har- bility. For several cases from the General monic fast-wave heating (HHFW) on Atomics DIII-D tokamak, a time-slice NSTX and was used for time-dependent analysis with full Monte Carlo neutral- HHFW studies this year. beam injected fast ions could be complet- The TRANSP Group’s collaboration ed in about three minutes on commodity with the authors of TORIC (Institut für hardware — well within the 20-min- Plasmaphysik, Garching, Germany) con- ute shot cycle time for DIII-D. Multiple FusionGrid compute servers can be employed to process multiple time points si- 22 Pre H-mode SN109067 multaneously. By using ElVis monitor- t = 360 msec

) NPA )

-1 20 ing, useful run results can be seen even 1/2

s TRANSP

before run completion. -3/2 18

There has also been signiﬁ cant prog- eV Normalization ress on TRANSP physics packages. The -2 16 cm

National Transport Code Collaboration -1 (NTCC), http://w3.pppl.gov/NTCC, re- H-mode (ster 14 t = 520 msec ceived an upgraded version of NUBEAM, flux/Energy ln(NPA TRANSP’s Monte Carlo fast-ion module, 12 Noise Level which has now been installed in General Atomic’s ONETWO transport code. In 020406080 100 collaboration with Lehigh University, a Energy (keV) detailed description of the NUBEAM Figure 4. TRANSP neutral particle analyz- package was completed. Fortran-90 and er simulations (versus particle energy) com- precision improvements enabled remov- pared to measurements on the National al of the upper limit on the number of Spherical Torus Experiment.

50 tinued. A modular interface for commu- al-purpose packages have been picked up nication of TORIC’s wave-fi eld solution and acknowledged by scientifi c users out- to the Fokker-Planck fast-ion solver was side the magnetic confi nement fusion re- defi ned and is being implemented. search community. Collaboration with Joint European In the early years of the NTCC proj- Torus (JET) physicists resulted in the de- ect, a foundation was laid in the form of velopment, installation, and validation of basic tools needed for collaborative scien- a new, generalized geometry fast analytic tifi c computing, such as packages to aid neoclassical resistivity module. The con- the creation of portable software, as well tributions by the JET team were made as basic numerical tools such as interpo- over the internationally shared TRANSP lation. As the project has matured, more code development collaboration system, sophisticated and larger integrated phys- which has been operational for more ics packages are being collected in the li- than twelve years. brary. The maximum radial resolution of In FY03, the following new modules TRANSP has been increased from 100 were contributed: to 400 zones, with various performance improvements made for high-resolution • CURRAY: ion-cyclotron range-of- operation. The fl oating-point precision frequencies ray-tracing code. of the entire TRANSP kernel — hundreds of subroutines — was systemati- • GA-TORAY: electron-cyclotron heat- cally increased from 32-bits to 64-bits, ing and electron-cyclotron current- using porting and conversion tools (fpre- drive ray-tracing code. proc and ftoken) supplied in the National • CYTRAN: cyclotron radiation trans- Transport Code Collaboration (NTCC) port package. modules library. In summary, the TRANSP effort, • FRANTIC: simplifi ed geometry well supported by the PPPL experimen- very fast neutral atom transport tal projects (NSTX and collaborations), package. along with allied efforts in the NTCC and in the SciDAC Fusion Collaboratory, • TR-CLIENT: client tools for continues to make progress over a wide TRANSP Collaboratory users. range of research activities. NTCC Modules are subject to a re- National Transport Code view process. A standing committee se- lects reviewers and votes to approve re- Collaboration Modules Library viewed modules; the approval status of In FY03, PPPL continued to make modules is clearly marked at the website. contributions to the NTCC Modules In FY03, the following modules were re- Library and to support the library web- viewed and approved: site, http://w3.pppl.gov/NTCC. In this role, PPPL not only submits its own con- • NUT: fast, semi-analytic three-di- tributions but also receives and packag- mensional code for neutral atom es contributions from other laboratories. transport in plasmas. There have been numerous downloads of NTCC software, both nationally and in- • ESC: toroidal magnetohydrodyna- ternationally. Many of the more gener- mic equilibrium solver.

51 Authors can, and frequently do, sup- Hodge projection to preserve the solenoi- ply signifi cant upgrades to existing mod- dal property of the magnetic fi eld. This ules. In FY03, signifi cant upgrades were code is currently being utilized in studies received for: of pellet injection in tokamaks, in studies of magnetic reconnection, and to evalu- • EZCDF: easy interface to NetCDF ate other possible uses of AMR in fusion portable fi le format. applications. To simulate pellet injection in toka- • GLF23: predictive transport model. maks, a trajectory for a spherical pel- • NUBEAM: Monte Carlo fast-ion let of frozen hydrogen is prescribed and package from TRANSP. an existing pellet ablation model employed. The result of the calculation • PEDESTAL: H-mode pedestal/ is that the ablated pellet mass is redis- edge model. tributed in the tokamak plasma due to • R8SLATEC: library of special func- large-scale MHD processes. Preliminary tions and mathematical tools. results of HFS (high-fi eld-side) and LFS (low-fi eld-side) launches are shown in The Princeton Plasma Physics Lab o ra- Figure 5. The top and middle images tory has contributed slightly more than show a density isosurface for the HFS half the modules currently in the NTCC and LFS launch respectively. The isosur- library, and is committed to responding faces shown in the computational do- to user requests for assistance with this main (right column, top and middle software. In FY03, signifi cant assistance rows) are superimposed with the out- was given to Institut für Plasmaphysik, lines (white) of the various grids which Garching, Germany, General Atomics, indicates that the mesh has been adapt- and the Lawrence Livermore National ed to follow the motion of ablated mass Laboratory. in the domain. The bottom panel shows The NTCC has proven to be a very density contours in a poloidal slice in- useful venue for software sharing. tersecting the center of the pellet. It is Experience gained in the NTCC proj- evident that the dominant transport ect will be extremely useful in larger of the pellet ablated mass is along the software collaborations planned for the magnetic fi eld lines. Nevertheless, mass future, such as the Fusion Simulation transport across fl ux surfaces in the out- Project. ward radial direction for both the HFS and LFS launches is observed. This is in Advanced Numerical Techniques qualitative agreement with the exper- Adaptive Mesh Refi nement Model imental observation of the differences of Pellet Injection into Tokamaks in effi ciency between HFS and LFS pel- An AMR (adaptive mesh refi nement) let launches. Detailed comparisons are MHD code using the Chombo frame- presently being made of these simula- work (website: http://seesar.lbl.gov/ tions and the corresponding experimen- ANAG/chombo/) has been developed tal data from the Tokamak Fusion Test in collaboration with researchers at the Reactor (TFTR) and the Joint European Lawrence Berkeley National Laboratory. Torus (JET). The code uses an eight-wave unsplit up- The AMR technique has proven itself winding numerical method coupled with to be extremely useful for enabling the

52 Figure 5. Top images show density contours associated with high-fi eld-side pellet injection. Middle images show corresponding contours for low-fi eld-side injection. Bottom image shows a poloidal projection contrasting high-fi eld-side (left) and low-fi eld-side (right) injection. calculation of certain localized phenome- solves to allow larger time steps, and the na in fusion experiments that would oth- incorporation of more complete extend- erwise be very costly or impossible to ed-MHD models of the plasma. These compute. Further developments in this will enable much more realistic and ef- area will include an improved treatment fi cient calculations of both reconnection of anisotropic heat conduction, implicit and pellet fueling.

53 GACO: Solving Differential Numerical Error Equations using Wave Packets 100 Many challenging plasma wave propa- FEM gation problems give rise to solutions that exhibit localized, fi ne-scale structures. 10-4 ε It is well known that short wavelength GACO features can occur in mode conversion -8 problems. For instance, the conversion 10 of magnetosonic into Bernstein waves requires the resolution of waves with dra- 10-12 102 103 104 matically different wavelengths. A similar Number of Degrees of Freedom situation arises with toroidally coupled Figure 6. A comparison of the accuracy Alfvén eigenmodes when Larmor radius of the of the linear fi nite element method corrections are included. (FEM) and the GACO code method when A numerical code (GACO) has been using the same number of elements in ap- developed that is based on the colloca- plication to the solution of a test problem tion method and expanding the solu- whose solutions are similar to Airy function in sinusoidal wave packets known as tions. Gabor functions. The Gabor functions have optimal localization properties in regime. The estimated number of FEM both Fourier (unlike low-order fi nite ele- nodes that would be required to match ments) and real space (unlike global spec- GACOS’s accuracy obtained using only tral methods) in the sense of minimiz- 300 degrees of freedom, can be estimated ing Heisenberg’s uncertainty principle. to be about 4 million. Similar to spectral methods, the Gabor basis functions are smooth and infi nite- Visualization and Data Streaming ly differentiable, allowing equations of The Computational Plasma Physics arbitrary order to be solved, at least in Group (CPPG) has been working with principle. Because the Gabor functions data from several theory codes, includ- effectively have fi nite support, the resulting M3D and GTC, as well as from ing matrix system is sparse. Thus, Gabor experimental analysis codes such as functions combine the best of spectral TRANSP and TSC. To accommodate methods and fi nite elements. such a wide range of codes, PPPL scien- The Gabor functions require far few- tists have been developing and utilizing er degrees of freedom to capture oscilla- several types of visualization software tory solutions than the linear fi nite ele- ranging from ElVis (for code monitor- ment method (FEM). This can be seen ing) to Ensight Gold (for parallel visu- in Figure 6 which shows that when solv- alization) running from the display wall ing an equation similar to the Airy equa- software. Furthermore, to handle the tion, which mimics a wave equation with large volumes of data which are being a linear cut-off, the method can be quite moved over to PPPL, researchers have powerful. Due to the high value of the been working on data management wave number (kL ~ 50π) in the propa- strategies to help assist this task. gating region, as many as 2,000 uniform- The ElVis software, being developed ly distributed nodes are required for the by the Computational Plasma Physics FEM to enter the quadratic convergence Group, has now been integrated within

54 the TRANSP code production system. pnode pnode pnode pnode pnode Users can visually monitor the data being pnode pnode pnode pnode computed as a job runs. Their input data is also displayed visually for verifi cation. Gigabit Switch Data monitoring is fully integrated with the FusionGrid Monitor so users can dis- head IBM SGI play their data in a browser and access Princeton SP Onyx it on the Internet from anywhere. The University Router National Fusion Collaboratory prepared Route a demonstration of this visualization ca- NERSC pability for data monitoring for the 2003 OC48 Supercomputing Conference (SC03). Microwave link OC192 CA ESNET Scientists at the Princeton Plasma 100M III OC192 Physics laboratory are now routinely using 1Gb Firewall high-end commercial software packages NYC OC3 to produce visualizations. The SciDAC codes, GTC and M3D, are using AVS/ Route PPPL Express to produce visualizations. This visualization capability has become an es- Gigabit Switch sential part of the computational progress for these researchers. The Computational pnode pnode pnode pnode pnode Plasma Physics Group is also investigating other software packages, including Figure 7. Illustration of high-speed data ParaView, VTK, and OpenDX. In col- streaming between three locations: Princeton laboration with NERSC, Ensight Gold University (top), NERSC (middle right), is now running on the PPPL visualiza- and PPPL’s local cluster (bottom). The fi rst architecture is a cluster of nine dual proces- tion cluster and being tested with very sor AMD 2100MP nodes with a gigabit in- large datasets generated by the GTC frastructure. The second is the IBM SP and code. The Laboratory has obtained a li- SGI at NERSC. The third is a cluster lo- cense for Ensight Gold, and it has been cal to PPPL with 18 dual processor nodes used remotely to visualize data that was where only fi ve nodes are shown. PPPL produced at and resides at NERSC using has an OC3 (155-Mbit) connection to the their 12 processor SGI Onyx. This ap- ESNET and a 100-Mbit connection to the proach is being investigated further. cluster at Princeton University. Data management has emerged as a key aspect to visualizing large datasets. Fusion tegrated with the GTC code. To enable scientists are computing very large sim- the data streaming, several APIs in C with ulations on remote supercomputers and Fortran-90 hooks have been built. This clusters. Data transfer has been a signifi - allows streaming data from a live GTC cant limitation to their work. In response simulation on a remote supercomputer to this problem, the CPPG has developed to a cluster which is local to the user. The techniques for high-speed transmission system is built on top of the Globus tool- of data from the remote machines to lo- kit, namely the APIs which are used for cal storage. This work on parallel stream- GridFTP. In the system POSIX pthreads ing, illustrated in Figure 7, was prepared are used to thread the I/O layer. Data is for publication at SC03 and has been in- copied from the main program to a buf-

55 fer. The thread is then activated and starts Workstations will be networked to the to stream a small piece of this data us- Display Wall and integrated via the ing GridFTP APIs. Data is then streamed Virtual Network Computer software. from the supercomputer to our local clus- Applications displayed on the worksta- ter on which each node runs a GridFTP tions will also be shown on the Display server. Typically, ten GridFTP streams Wall. per processor are sent. Data is written to The Access Grid node is operational, disk on the nodes of the local cluster. several network problems having been re- The Computational Plasma Physics solved. Scientists can attend research fo- Group has also designed and started de- rums, meetings, and seminars and col- ployment of a new collaborative Display laborate with other institutions over the Wall for the NSTX Control Room. Access Grid.

56 Off-site Research

he Princeton Plasma Physics particles produced by the fusion reac- Laboratory’s (PPPL’s) Off-site tions in the Joint European Torus (JET) T Research Department seeks to in England. Areas of special topical em- answer key scientifi c questions in mag- phasis include transport and turbulence netic fusion research by working as mem- in larger-scale high-temperature plasmas, bers of multi-institutional teams and by large-scale stability, heating and current bringing PPPL’s tools and understand- drive, and energetic particle effects. The ings to leading fusion programs world- topical research is pursued on a range of wide. The resultant teams exploit the syn- confi gurations including both tokamaks ergies of the integrated institutions, using and stellarators, which share the toroidal the best facilities and tools for answering topology with closed magnetic fi eld lines the questions. The PPPL researchers are in the plasma core, eliminating the losses not mere suppliers to the remote pro- along the fi eld lines. grams — they are partners on integrated PPPL’s enabling tools include diagnos- teams both at the remote facility and via tics, computational simulation and anal- remote access to the experimental equip- ysis codes, and antennas for launching ment and data. They compare and con- and receiving waves in frequencies rang- trast phenomena at different scales and in ing from the ion-cyclotron to the lower- different confi gurations and extend inno- hybrid to the electron-cyclotron frequen- vations and discoveries to other facilities. cies. The waves are typically launched They bring PPPL’s strengths in experi- with the capability of both heating and ment design, diagnostics, data analysis, current drive. experiment and theory comparison, engineering design, and operations support DIII-D Collaborations to the remote collaborations. The collaboration with General Atom- PPPL’s major efforts have included ics’ DIII-D in FY03 continued to make studies of the control of large-scale in- major contributions toward the develop- stabilities at high plasma pressure on the ment of the Advanced Tokamak (AT) re- DIII-D tokamak at General Atomics in actor concept through active control of San Diego; control and measurement of resistive wall modes, optimized shap- the profi les of plasma properties, espe- ing studies for high plasma beta opera- cially by lower-hybrid and current-pro- tion, fast-wave hardware enhancements fi le measurements on the Alcator C-Mod for plasma current profi le control, diag- tokamak at the Plasma Science and Fu- nostic upgrades and scientifi c advances sion Center at the Massachusetts Insti- for understanding microturbulence and tute of Technology; and discovery of new plasma rotation. In addition, PPPL has modes of interaction between the plasma provided operations support both for the and energetic particles, such as the alpha DIII-D tokamak and for the auxiliary-

57 heating and current-drive systems on the null plasmas. Ideal stability calculations machine. performed for these discharges are in good agreement with the experimental Stability scaling of normalized beta with shaping An extensive study of the effect of and show that these plasmas routinely plasma shaping on ideal-MHD stabili- operate above the calculated n = 1 no- ty for DIII-D AT-like plasmas was per- wall limit and disrupt near the ideal-wall formed in FY03. Shaping of the plasma beta limit. The calculations indicate that boundary is a critical variable to opti- further profi le and shape optimization is mize plasma stability, along with the pro- needed to increase the normalized beta fi les of the plasma current and plasma well above four as desired for enhanced pressure. A study was performed which AT performance. varied the elongation, triangularity, and In practice, the fi nite resistivity of the outer squareness of the plasma, assum- plasma boundary limits the attainable ing 100% noninductive current fraction pressure when compared to calculations composed of neutral-beam current drive assuming a perfectly conducting wall. Fi- (NBCD), electron-cyclotron current nite wall resistivity gives rise to new edge drive (ECCD), and bootstrap current. modes that need to be stabilized. In or- The n = 1, 2, 3 and n = infi nity ideal- der to stabilize these resistive wall modes MHD modes were examined where n is (RWMs) a resonant fi eld perturbation the toroidal mode number. It was found needs to be induced using external coils, that enhanced elongation is the most ef- and this resonant fi eld needs to feed back fective way to raise the plasma pressure, on the growing boundary modes. So far since it raises the critical pressure for the the DIII-D program has demonstrat- onset of all the mode numbers, and it ed control of the RWMs by maintaining also enhances the bootstrap current frac- rapid plasma rotation; this rotation pre- tion. The study found that triangularity vents the growth of modes, and the ro- increases the pressure threshold for low-n tation is better maintained when nonax- kink modes; however, its effect on high-n isymmetric error fi elds are minimized. modes is less pronounced. An interesting Some indication of direct feedback con- outcome of this study is that the n = 2 trol of the RWM was obtained in FY03 and n = 3 modes always have lower stable with the new I-coils, however much is pressure values than the n = 1 mode with left to do to demonstrate the stabilization wall stabilization. In principle, the lower of these modes by external currents. This threshold for n = 2, 3 modes should limit will be a key objective of the FY04 cam- access to high-beta regimes, however it is paign. not clear how the n = 2 and n = 3 modes manifest themselves. This will be a sub- Confi nement and Transport ject of experimental study in FY04. The plasma pressure attainable within In addition to the modeling of de- a particular magnetic geometry depends tailed shape, experiments were per- critically on the nature of the heating formed to determine the beta limits in profi le and the microinstabilities and col- AT plasma discharges as a function of lisional transport processes which deter- plasma shape. Double-null discharges mine the rate of energy loss from the plas- were found to have beta limits 10-15% ma. In addition, microinstabilities can be higher than the standard upper single- strongly modifi ed by and can also strong-

58 ly affect plasma rotation, and this rotation 3 ) can have a profound effect on plasma sta- 4 10 bility. To understand the interaction be- x Experiment tween plasma turbulence, pressure-pro- 2 fi les, and rotation-profi les, fundamental studies of the turbulence properties and 1 associated transport are required. Theory A key collaboration effort between PPPL and General Atomics (GA) has been 0 the development of a central Charge-ex- Poloidal Velocity (m/s) ( Poloidal Velocity change Recombination (CER) system -1 for plasma-rotation measurements (Fig- 0 0.2 0.4 0.6 0.8 1.0 ure 1). The system can measure profi les Normalized Minor Radius of both toroidal and poloidal rotation of Figure 2. Inferred poloidal velocity profi les the plasma. However, detailed modeling from CER measurements in a quiescent is required to separate out atomic phys- high-confi nement mode plasma (black) and ics effects from the true rotation of the the neoclassical estimate (blue). plasma. Rapid progress has been made in FY03 to allow for the accurate deter- CER measurements. Detailed model- mination of the poloidal rotation from ing has led to a relatively simple upgrade to the existing CER viewing system on DIII-D, which will allow for much more precise poloidal-rotation measurements in FY04. Preliminary comparison of the neoclassically predicted poloidal velocity with the fully corrected CER measurements for a quiescent high-confi nement mode (H-mode) plasma discharge in Fig- ure 2 indicates an order of magnitude discrepancy between the two. The origin of this discrepancy will be the subject of extensive study in FY04. In addition to the CER measurement of plasma rotation, data from poloidal turbulence velocity measurements using the University of California at Los Ange- les (UCLA) refl ectometer were analyzed using the two-dimensional (2-D) full- wave refl ectometer code, FWR2D, developed at PPPL. The poloidal turbulence velocities compared well to the E×B velocity obtained from the edge CER di- Figure 1. Vertical and toroidal sightlines of agnostic on DIII-D (Figure 2). Future the central Charge-exchange Recombina- plans include the detailed comparison of tion (CER) system on the DIII-D tokamak refl ectometer and CER estimates of po- at General Atomics. loidal rotation in the plasma core.

59 A new collaboration was begun in FY03 lows the properties of the microfl uctua- to understand the behavior of microfl uc- tions to be inferred from the properties tuations in DIII-D through a collabora- of the measured electric fi eld at the an- tion with UCLA on poloidal-correlation tenna shown in Figure 3. A comparison refl ectometry. By launching microwaves of the poloidal-rotation velocity mea- into the plasma and seeing the refl ection sured using Beam Emission Spectrosco- of waves from a plasma cutoff, it is possi- py (BES), Poloidal Refl ectometry, and ble to infer the properties of the microin- CER is shown in Figure 4. The fi gure instabilities at the refl ecting layer. If an ar- dicates that the poloidal rotation mea- ray of these receivers is arranged in the sured using the CER system is in qualita- vertical direction (Figure 3), then the po- tive agreement with the poloidal rotation loidal propagation of the refl ected waves of the turbulent fl uctuations, while the can be inferred. This in turn reveals the BES disagrees. radial-electric fi eld in the plasma. Figure Plasma transport modeling and appli- 3 shows the geometry of the poloidal cor- cations of the TRANSP code is another relation refl ectometer system on DIII-D. important area of activity for PPPL re- One launcher and two receivers allow for searchers. TRANSP analysis of DIII-D the poloidal propagation velocity of the discharges is now being done using the fl uctuations to be inferred from the time- PPPL TRANSP servers via the Fusion delay correlation of the signals measured Grid tools developed by the Department on the pair of poloidally displaced receiv- of Energy Offi ce of Science’s Scientifi c ers. Modeling of the refl ected waves is Discover through the Advanced Com- performed using a 2-D full-wave analy- puting Program (DOE SciDAC)-fund- sis developed at PPPL. The modeling al- ed National Fusion Collaboratory Proj-

100

Antennae 0

Vertical Height (cm) Vertical -50

-100 200 250 300 350 Major Radius (cm) Figure 3. Plasma density proﬁ le (orange) together with incoming and outgoing microwave beam (blue). The microwaves reﬂ ect from the plasma and are received on two detectors (antennas) outside the plasma.

60 20 PPPL’s research in this area is the recom- Plasma Core missioning and upgrading of the fast- 15 wave systems operating at 60 and 117 Reflectometer MHz. This collaboration is now in its 10 initial stages, and represents a combined effort involving three research laborato- CER ries: the Oak Ridge National Laboratory 5 BES (ORNL), PPPL, and GA. Initial success was achieved in establishing operation of 0

Poloidal Velocity (km/s) Poloidal Velocity the 60-MHz and one of the 117-MHz launchers, allowing antenna-loading and -5 voltage-standoff studies to be performed. -10 -8 -6 -4 -2 0 2 Distance from Separatrix Operations Support Figure 4. Refl ectometer measurement of poloidal rotation (green) compared to the PPPL continues to provide valuable charge-exchange recombination measure- on-site support of tokamak operations ments (red), and the beam emission spec- on DIII-D. In addition, PPPL has un- troscopy measurements (blue). dertaken the role of supporting the operation of the fast-wave systems on DIII-D ect. The new tools allow researchers to in collaboration with GA and ORNL re- submit runs remotely (from GA), allow searchers. the calculations to proceed at PPPL, and permit easy access to the results from an Alcator C-Mod Collaborations MDSplus server located on site at GA us- PPPL’s research collaboration on the ing the “Globus” Computational Grid Alcator C-Mod tokamak at the Plasma software. Science and Fusion Center at the Mas- A new collaboration activity aimed at sachusetts Institute of Technology (MIT) identifying the physical causes and effects continued to advance understanding in of fi ne-scale instabilities known as elec- areas key to ITER (“The Way” in Latin) tron temperature gradient (ETG) modes and to improve the attractiveness of the was also initiated in FY03. This work is tokamak as a possible reactor. The fol- in collaboration with UCLA physicists lowing accomplishments are particular- who are leading the effort to measure the ly signifi cant: short-scale instabilities with high-k scattering diagnostics. PPPL’s role is in the • PPPL researchers contributed sub- detailed microstability modeling of these stantially to the fusion program’s sci- plasmas. entifi c knowledge of radio-frequency (rf) heating this year. As the hard- Wave-plasma Interactions ware-intensive modifi cations to the The key element of PPPL’s role in ion-cyclotron range-of frequencies wave-particle interactions on DIII-D is (ICRF) antennas have approached in current-drive and current-profi le con- maturity, substantially greater em- trol. Advanced Tokamak research seeks to phasis has been given to the phys- replace inductive (fi nite duration) plas- ics of radio-frequency heating and ma currents with steady-state noninduc- the study of wave-particle interac- tively driven current. A key element of tions. Operational support contin-

61 ued with both PPPL physics and en- spectrometer was installed on Alca- gineering presence and input. tor C-Mod during the NSTX downtime and initial measurements were Participation in the study of the ef- • made. fects of high-power heating on plasma transport and stability was ex- Radio-frequency Heating tended through the use of nonlinear PPPL physicists and engineers have simulation codes and diagnostic continued to be strongly involved in the upgrades and detailed comparisons Alcator C-Mod ICRF program, includ- between predictions and observa- ing hardware improvements and partic- tions. ipation in experiments, as well as mod- • The Gas Puff Imaging diagnostic eling of wave-particle interactions. The was further improved, allowing di- PPPL-designed and jointly modifi ed rect visualization of the macroscopic four-strap ICRF antenna (Figure 5) now structure of edge turbulence. Mod- operates with up to ~3 MW of radio- eling of the turbulence images has frequency power into the plasma. It has been extended. been operated at high power in heating phasing (0°, 180°, 0°, 180°) and both co- • Nonlinear simulations of the effect (0°, 90°, 180°, 270°) and counter- (0°, of plasma turbulence on core trans- -90°, -180°, -270°) current-drive phas- port continued, as have simulations ing. The plasma heating effi ciency was of the role of instabilities on the for- identical for the three-phasing confi gura- mation of internal transport barriers tions (Figure 6), and equal to the equiva- in off-axis-heated H-mode plasma lent heating power effi ciency from either discharges. of the other two antennas. Total ICRF • Two new higher-frequency channels heating power using all three antennas is of the C-Mod microwave refl ectom- now up to 5 MW for 0.5 seconds. eter became operational allowing the Wave-particle interaction studies have measurement of plasma fl uctuation focused mostly on D(H) minority heat- farther up the edge pedestal. ing and mode conversion. Alcator C- Mod’s set of ICRF antennas and its ex- • The Motional Stark Effect diagnostic became operational, and careful calibrations are in progress to determine its range of usefulness when coupled with the present diagnostic neutral beam. • The lower-hybrid launcher design- and-fabrication project was completed in April, 2003. Subsequent preoperational tests revealed manufacturing defects that are being cor- Figure 5. The PPPL-designed four-strap rected. ion-cyclotron radio-frequency antenna, as installed and modifi ed in conjunction with • The National Spherical Torus Ex- the Plasma Science and Fusion Center at periment (NSTX) X-ray crystal the Massachusetts Institute of Technology.

62 +90° -90° Heating 2 1

0 Power (MW)

0.06 Radio-frequencey

(MJ) 0.04

Stored Energy 3

) 2 -2

1 Central Ion 20 1 10 Temperature (keV) Temperature x 0.8 Electron Line

6 α Density ( D

4 (A.U.) 1.5

(MW) 0.5

Radiated Power 0.6 0.8 1 0.6 0.8 1 0.6 0.8 1 Time (sec) Figure 6. Comparison of antenna performance and plasma response to three different antenna phasing settings: +90° current drive, -90° current drive, and heating. The plasma stored energy, density rise, edge light, and radiated power are the same. The sawtooth period is changed.

cellent set of diagnostics (high-precision siderably richer in phenomena than pre- electron-cyclotron emission to determine viously thought (Figure 9). wave power deposition through electron PPPL radio-frequency engineers con- heating and phase contrast imaging to tinued to work closely with their coun- detect wave propagation through density terparts at MIT and traveled to Alcator ﬂ uctuations) make it the premier exper- C-Mod to participate in transmitter re- imental facility to study wave propaga- tuning and frequency response optimization and absorption in the ion-cyclotron range of frequencies. The ﬁ rst experimen- 380 80.53 tal observation of the mode conversion of an incoming fast wave to an ion cyclo- 360 80.50

tron wave, ﬁ rst predicted theoretically (kHz) f (kHz) RF ∆ by F.W. Perkins in 1977, was made (Fig- 340 f ure 7). The dispersion curves showing 320 80.47 the location of the conversions process- -10 -5 0 510 -1 es are shown in Figure 8. These extend- kR (cm ) ed measurement capability and improve- Figure 7. Contour plot of the Fourier-ana- ments to the full-wave simulation code lyzed Phase Contrast Imaging (PCI) data. TORIC, benchmarked against the one- The bright area indicates an ion-cyclotron dimensional PPPL code METS, indicate wave propagating back towards the anten- that the mode-conversion process is con- na. (From Y. Lin, MIT.)

63 107 tion. Frequent exchanges of information IBW PCI Chords and ideas have occurred throughout the 106 ICW year. 105 2 ⊥ -1 Plasma Turbulence Studies n 4 5

Downshifted Hallatschek and Rogers and the BOUT ICW code of Xu and Nevins, which uses ex- 20 perimental profi les and realistic magnetic geometry. Turbulence studies from the plasma edge inward toward the plasma core were 0 enhanced with the addition of 130 and Z (cm) 140-GHz channels (higher frequency, greater penetration) to the existing Alca- -20 tor C-Mod microwave refl ectometer diagnostic. Plasma discharges into which Upshifted ICW lithium pellets were injected were studied during the fi rst experimental phase. Ini- -20 -10 0 10 20 X (cm) tial measurements indicate that fl uctuations in the plasma core are much low- Figure 9. Plasma cross section with super- er in frequency than those at the plasma posed wave electric fi elds calculated with edge. the TORIC simulation code. Shown are the fast wave (FW) propagating toward the cen- Nonlinear modeling of the effect of ter from the antenna at the right edge of the turbulence on transport in the plasma plasma, the mode-converted ion-Bernstein core continued. Theoretical transport wave (IBW), and the mode-converted ion- predictions were compared with experi- cyclotron wave (ICW). (From J.C. Wright, mental data to determine whether drift- MIT.) type instabilities could be predicted to

64 Figure 10. Sketch of the Gas Puff Imaging diagnostic. Gas is puffed radially into the plasma from the outer wall. A telescope near the edge of the vacuum vessel looks along the magnetic ﬁ eld and views the light emitted from the gas due to electron impact excitation. The resulting light pattern is brought outside the vessel through a coherent ﬁ ber-optic bundle and photographed with a fast camera.

Single frame from movie with 6 Msec exposure time in DA light emission. Shot #1030523030

Magnetic F 0 ield Line

-2 Poloidal (cm) -4 2 61014 18 Toroidal (cm) Figure 11. Photograph of the Alcator C-Mod plasma edge looking radially inward. The short exposure time of six microseconds clearly reveals edge turbulence in the form of stria- tions oriented along the magnetic ﬁ eld.

Figure 12. Movie of plasma edge turbulence taken with the Gas Puff Imaging diagnostic. As the bright “blob” moves outward, it becomes more compact and evolves into the striation seen in the radial view (Figure 11).

65 be responsible for transport in the core the experiment at the trigger time (Fig- of typical H-mode plasmas in Alcator C- ure 13). Mod. A number of nonlinear gyrokinetic simulations of turbulent transport due to Current Profi le Measurements long wavelength electrostatic drift-type MIT’s installation of a Novosibirsk- instabilities were performed. Simulations built diagnostic beam on loan from the of core turbulent transport in an Alcator an experiment at the University of Pad- C-Mod enhanced D-alpha H-mode plas- ua, Italy, has resulted in suffi cient signal ma were extended to higher wave num- from the Motional Stark Effect diagnostic bers and fi ner resolution. The results did that analysis and attempts to extract cur- not change appreciably, indicating that rent density information are under way the results are well converged. A number with emphasis on the outer region, where of very long simulations (with lower res- the signal is strongest. Several iterations olution) have provided “test data” used to in mounting internal optical elements to develop an algorithm for estimating the withstand disruption shock appear to have uncertainty in the predicted fl uxes. These been successful. Initial beam-into-gas ex- calculations were carried out on the Fu- periments have been carried out, with pre- sion Energy Science Pilot Topical Com- set and precisely known toroidal and po- puting Facility at PPPL, and kept essen- loidal magnetic fi elds determining the tially all of the 128 CPUs occupied for magnetic pitch angle. These calibrations most of several months. have revealed perturbation by unpolar- Gyrokinetic simulations of plasma tur- ized and circularly polarized light created bulence with the GS2 code are being car- by the beam, and plans are underway for ried out to examine H-mode, rf-heated an extremely precise in-vessel calibration experiments that exhibit internal trans- at the next Alcator C-Mod opening. port barriers (ITBs). Simulations are focused on the trigger time shortly before 1.3s the internal transport barrier is estab- ) 5 -3 1.5s lished. Linear calculations show stable m 1.1s long wavelength turbulence at the barri- 20 4 er, without invoking suppression by E×B 0.9s shear. At the internal transport barrier, no Time of strongly growing trapped-electron mode 3 Interest (TEM) nor ion temperature gradient 0.7s (ITG) mode is found, although an elec- 2 0.5s

tron temperature gradient (ETG) mode Electron Density (10 is present. Outside the internal transport barrier, clear signatures are found for to- 0 0.2 0.4 0.6 0.8 1.0 roidal ITG and ETG modes. In the plas- Normalized Plasma Radius (r/a) ma core, TEM modes are unstable in the Figure 13. Evolution of an internal trans- electron drift direction, but not ITG, nor port barrier in the Alcator C-Mod plasma. ETG. Reduced instability growth rates Density starts to rise in the plasma core at predicted at the barrier are consistent with the “time of interest” when the barrier is es- the observed reduced transport. Nonlin- tablished. The three vertical green stripes ear simulations were performed which re- indicate the radial locations at which the produce the linear results and agree with stability calculations are performed.

66 Lower Hybrid Current Drive PPPL undertook the design and fabrication of a lower-hybrid wave launcher (Figures 14, 15, and 16) capable of driving current in the Alcator C-Mod plasma off-axis in order to modify the internal magnetic fi eld profi le in such a fashion as to extend Alcator C-Mod operation into the Advanced Tokamak regime. The launcher was delivered to MIT in April, 2003, but preoperational inspection and Figure 16. The lower-hybrid launcher’s rear testing revealed defective electroplating. waveguide following assembly at PPPL. Rework of the window assembly is pres- This component includes interfaces to the microwave power sources, microwave power splitter, directional couplers to measure forward and refl ected microwave power, and phase shifters to provide the proper wave front to the plasma.

ently in progress with MIT, with completion and installation on Alcator C-Mod now anticipated for May 2004.

X-ray Crystal Spectrometer An X-ray crystal spectrometer designed Figure 14. The lower-hybrid launcher’s cou- to measure ion temperature and poloi- pler, the component adjacent to the plasma. dal rotation on NSTX was installed on The microwave grill is surrounded by boron nitride protective tiles to shield it from plas- the Alcator C-Mod tokamak during the ma heating. NSTX downtime (Figure 17). Initial argon X-ray spectra were obtained (Figure 18) and analysis of the data is in progress. The resolution of technical problems with high X-ray backgrounds and detector count rate limitation found on C-Mod helped to qualify the equipment for use on NSTX.

International Collaborations It has long been recognized that fusion research can beneﬁ t from interna- Figure 15. The lower-hybrid launcher’s for- tional collaboration. The U.S. Depart- ward waveguide on the PPPL vacuum test ment of Energy (DOE) has invested stand. This component includes a radi- signiﬁ cant effort in developing interna- al drive system to vary the coupler/plasma tional collaborations with facilities that separation and optimize microwave power present unique opportunities for U.S. deposition in the plasma. scientists to advance fundamental un-

67 tion also present a major opportunity for the U.S. to advance steady-state plasma research. In addition, the development of a strong stellarator program in the U.S. will beneﬁ t from close coupling with researchers on large-scale stellarator facilities worldwide.

Joint European Torus Collaboration The primary goal of the Joint Euro- pean Torus (JET) collaboration is to ad- Figure 17. The NSTX X-ray crystal spectrometer installed on the Alcator C-Mod dress burning plasma physics issues on a at the Massachusetts Institute of Technol- scale and in a parameter regime not ac- ogy. The Alcator C-Mod tokamak is at the cessible to domestic fusion facilities. top middle of the picture, the X-ray crystal Now that the Tokamak Fusion Test Reac- spectrometer is under the circular plate at tor has been decommissioned, JET is the the lower left, and the position-sensitive X- only facility in the world capable of car- ray detectors and electronic equipment are rying out deuterium-tritium experiments outside the picture to the right. in the near term (5-10 years), with the potential to advance fundamental understanding of alpha-particle-driven instabilities. Fast-particle Research: A key element of the JET collaboration is the understanding of fast-ion behavior in the plasma. In a deuterium-tritium (D-T) power plant, highly energetic alpha particles will be produced and these will be the dominant heating source for the plasma. It is therefore essential to determine if the Figure 18. Energy spectrum of argon X-rays alpha particles produced by the D-T re- emitted by an argon gas-puff-injected into actions will be conﬁ ned for the time re- the Alcator C-Mod plasma. This spectrum quired to impart their energy to the is an overlay of four spectra from different plasma. Understanding the physics of in- vertical positions in the plasma. The hori- stabilities driven by fusion alpha particles zontal axis represents X-ray energy, and con- is a key element of the PPPL collabora- sists of primary plus satellite X-ray lines. tion on JET. Gerrit Kramer (PPPL), in collabora- derstanding in strategically important tion with JET scientists, has recently ana- areas for the development of fusion en- lyzed Toroidal Alfvén Eigenmodes (TAEs) ergy. Key among these is the pursuit of on JET, revealing the ﬁ rst evidence for burning plasma science in facilities that the existence of odd-parity TAE modes. approach the dimensionless parameters Odd-parity TAEs are predicted to exist relevant to a future burning plasma ex- alongside even-parity TAEs, but are usu- periment such as ITER. Fully supercon- ally much more strongly damped than ducting tokamaks now under construc- the even mode. The work demonstrated

68 the fi rst clear evidence for the existence of cy (UKAEA), and the Max Plank Insti- such modes consistent with long-stand- tute in Garching, Germany. The project ing theoretical predictions. leader is Doug Darrow of PPPL. The di- More recently, a joint experiment be- agnostic will measure lost energetic ions tween PPPL and JET scientists revealed and alpha particles in JET using scintilla- the existence of a very large number of tion and Faraday cup detectors located at Cascade modes, based on interferometric the plasma boundary. Installation of the measurements taken of the plasma interi- diagnostic is expected during the 2004 or. Cascade modes are driven by energet- machine opening. ic ions in reverse magnetic shear plasmas On the theory front, a new nonpertur- and may be excited in a fusion pow- bative version of the NOVA code called er plant. The large number of observed NOVA-KN (Kinetic Nonperturbative modes is shown in Figure 19. Magnetic NOVA) was applied to JET plasmas in diagnostics are not capable of observing which n = 1 MHD activity was driv- these modes, due to the localization of en using high-energy ICRH H-minori- the modes in the plasma core. This sug- ty ions. NOVA-KN identifi es both n = 1 gests that a future burning plasma exper- resonant and ideal-MHD modes, consis- iment will need to detect such modes us- tent with the two distinct aspects of this ing interferometers rather than magnetic mode. The predicted mode frequency of probes. the resonant branch corresponds to the Theoretical analysis of fast-ion phe- fast-ion drift precession frequency, which nomena must be matched by enhanced is characteristic of fi shbone modes fi rst diagnostics aimed at revealing the behav- identifi ed on the Poloidal Divertor Ex- ior of energetic ions in the plasma. As part periment (PDX) tokamak. The NOVA- of the PPPL and U.S. collaboration on KN mode is being developed by N. Gore- fast-ion physics, a new fast-ion-loss diag- lenkov and C.Z. Cheng of PPPL. nostic is being developed in collaboration Radio-frequency Technology Devel- with the Colorado School of Mines, the opment: As part of the JET Enhance- United Kingdom Atomic Energy Agen- ments Program (JET-EP) a new ITER-

160 9 140 120 8 100 Log 7 80

Frequency (kHz) 60 6 40 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 Time (sec) Figure 19. Spectrum of interferometer data versus time for a plasma discharge in which strong Cascade modes are induced. The Cascades chirp in frequency as the minimum q-value decreases.

69 relevant ICRF antenna is to be added tive impurity particle confi nement time to JET during the 2004 opening. This should increase with the fraction of sput- project, a multi-institutional collabora- tered carbon ionized in the main cham- tion between PPPL, ORNL, and the Eu- ber SOL, and decrease with machine size ropean Union, was initiated to proto- and SOL density. type the new antenna design to be used Transport Physics: Reliable predic- on JET. PPPL is responsible for the de- tion of the thermal transport in proposed sign and construction of the prototype next-step burning plasma experiments is antenna enclosure box, Faraday shield, a key task confronting the international and protective tiles. The radio-frequency fusion community. Because of its large technology development group at PPPL size and its use of strong radio-frequen- completed construction and assembly of cy heating, JET provides an ideal oppor- these items, and extensive testing was car- tunity for testing our predictive transport ried at a special test facility at ORNL. models against experiments in regimes Divertor Physics and Impurity Screen- where momentum and energy input can ing: One issue in a future burning plasma be decoupled. Microstability analysis of experiment is whether the core contami- JET plasmas using the GS2 code per- nation will be adequately small. Impuri- formed by R. Budny of PPPL suggests ties (particularly from carbon tiles) lead that the E×B shearing rate is unnecessary to the dilution of the plasma which de- to stabilize microturbulence in reverse- grades fusion performance. The Labora- magnetic-shear plasmas. The analysis in- tory has been a major contributor to the dicates that turbulence-suppression can science of divertors on JET. James Stra- be accomplished with equilibrium cur- chan (PPPL) led the JET carbon screen- rent profi le control. This has major im- ing experiments performed using meth- plications for sustaining internal trans- ane gas injection. In fi scal year 2003, the port barriers in future ITER plasmas. earlier carbon screening experiments in In addition, PPPL has been collab- low-confi nement mode (L-mode) plas- orating with JET and the Meg Ampere mas were extended to reverse magnetic- Spherical Torus (MAST) Group by profi eld plasmas. The methane screening re- viding and maintaining the TRANSP sults indicate that similar screening was plasma analysis code (using it to analyze seen in forward-and-reverse magnetic plasmas) and by training physicists at JET fi elds in spite of the fact that the scrape- and MAST to run TRANSP at PPPL via off layer (SOL) fl ow changed dramat- the FusionGrid. Recently TRANSP is ically. In support of these observations, being used to determine the transport simulations using the EDGE2D code ac- of trace tritium from recent gas-puff and tually indicate a small effect of the SOL neutral-beam-blip experiments. fl ow on the carbon screening magnitude. Another result of the EDGE2D calcula- JT-60U Collaboration tions has been the development of a size- The collaboration with the Japan scaling relationship for the carbon con- Atomic Energy Research Institute tent of an all-carbon tokamak. Assuming (JAERI) on the JT-60U tokamak centers other machines were composed of the on negative-ion-beam development. Ob- same materials, conditioned in the same servations by the JT-60U neutral-beam manner as JET, then the carbon content group in collaboration with PPPL’s Lar- per sputtered carbon atom and effec- ry Grisham revealed that the horizontal

70 beamlet steering in the JT-60U negative A key element of our collaboration is ion sources was not producing the desired analysis of the W7-AS equilibrium us- focusing of the overall beam envelope. It ing the PIES code, developed at PPPL, was concluded that this must be due to which self-consistently includes mag- the asymmetric space charge forces aris- netic islands and stochastic regions. The ing from the beam compression. An ex- preliminary PIES results thus far show a periment was designed in fi scal year 2003 correlation between the attainable pres- to determine whether the space charge sure values in the W7-AS experiment responsible for the lack of focusing origi- and the onset of magnetic stochasticity nated in the drift region after the acceler- in the outer part of the plasma. The anal- ation grids, or in the accelerator grid re- ysis suggests that the beta limits attained gion. The experiment showed that the on W7-AS correspond to the breakdown space charge causing the lack of focusing of good fl ux surfaces. For the purposes is in the accelerator, where it cannot be of this study, a modifi ed version of the compensated. Since the space charge pa- PIES code was produced, allowing the rameters for the ITER beam design will specifi cation of a fi xed, experimentally be similar to the JT-60U parameters, and determined pressure profi le, and apply- since the present ITER design reported- ing an appropriate model for the pres- ly uses a similar aperture displacement sure-driven current in stochastic regions. beamlet steering technique, this suggests The modifi ed code has been applied to that the ITER beamlet steering design a series of experiments for studying the may need to be revised. infl uence of control coil current on the attainable beta. The control coils, in- Stellarator Collaboration stalled to control the island divertor, are With the rise of the compact stellara- expected to infl uence the integrity of the tor program in the U.S., there is renewed fl ux surfaces in the experiment. A series interest in international collaboration on of PIES calculations has been performed existing large-scale facilities in Japan and for two different values of the control- Europe. In FY03, the PPPL collabora- coil current and for a range of beta val- tion centered on the Wendelstein-7 Ad- ues. The confi guration with higher at- vanced Stellarator (W7-AS) in Garch- tainable beta is calculated by the code ing, Germany. In 2003, the collaboration to sustain better fl ux surface quality as focused on analyzing the 2002 experi- beta is raised. ments, where plasmas were maintained quiescently at or near the pressure lim- KSTAR Collaboration it for more than 100 energy confi nement The Korea Superconducting Tokamak times. The limiting pressure appears to Advanced Research (KSTAR) device will not be due to macroscopic instabilities, be the one of the world’s fi rst tokamaks as often observed in tokamaks, but rath- to be fully superconducting. The pro- er to a saturation in confi nement. MHD posal to establish KSTAR as an interna- instabilities, when observed, saturate and tional user facility for the advancement do not inhibit access to higher pressures. of steady-state tokamak physics is an ex- The maximum pressure is observed to de- citing prospect for the world fusion pro- pend on the equilibrium magnetic con- gram. The device will begin operation fi guration, and scales like an equilibrium in late 2005, and active efforts are being limit in some cases. made to involve the international com-

71 munity early in the KSTAR program to crowave Launcher needed for initial plas- accelerate the development of the project ma breakdown and current-drive studies and its attainment of peak performance (Figure 20). In 2004 the launcher fabri- parameters. In FY03, PPPL completed cation will begin and launcher delivery is the designs for the electron-cyclotron Mi- planned for 2005.

Figure 20. A three-dimensional rendering of the Microwave Launcher being fabricated by PPPL for delivery to KSTAR in 2005. Shown is the steering mirror that will direct the microwave beam into the plasma.

72 Space Plasma Physics

esearch in the Space Physics existence of nonlinear dependencies in Group at the Princeton Plasma the time series and the predictability of R Physics Laboratory (PPPL) em- the system. The approach taken to de- phasizes understanding solar and magne- tect higher-order nonlinear statistical de- tospheric activity and how coupling be- pendencies is to examine the cumulants tween solar activity, the magnetosphere, of the probability distribution of an em- and ionosphere can affect the dynamical bedding vector that captures the under- evolution of the solar-terrestrial system. lying dynamics of the system. By com- Progress in four areas is described in this paring these cumulants with “surrogate” report: (1) information-dynamical mod- data constructed to share various statisti- eling of the magnetosphere, (2) self-con- cal properties with the original data set, sistent ion cyclotron heating in the au- it is possible to test various hypotheses roral ionosphere, (3) kinetic ballooning about the data. instabilities for substorm onset, and (4) To illustrate how the method can be fl ux rope acceleration and enhanced mag- applied to magnetospheric data, hour- netic reconnection in solar fl ares. ly averaged time series of Kp indices is considered. The Kp index is a measure of Information-dynamical the planetary disturbance level. Kp rang- Modeling of the Magnetosphere es from 0 to 9 with increments of 1/3. One of the problems of greatest practi- Higher Kp values mean more intense cal importance in the area of space phys- disturbance levels and the scale is loga- ics is that of predicting the magnetospher- rithmic. The Kp index is based upon the ic response to solar wind input. This is spread during the stated time interval bean area of active research in space phys- tween the largest upward and downward ics and is of great importance because excursions of magnetometer readings space weather can: (a) impact scientif- over a number of ground-based stations. ic, communication, and defense satellite The years 1975 and 1987 are representa- operations and (b) disrupt power grids tive of a solar minimum while 1980 and and ground communications. There- 1990 are representative of a solar maxi- fore, there is a high demand for models mum and the responses are shown in Fig- that can predict geomagnetic activity ac- ure 1. During a solar minimum, sunspot curately based on solar wind parameters activity is signifi cantly reduced and the as input, a demand that will likely to in- solar wind is steadier, consequently, one crease even more with the nation’s in- expects the dynamical response of the creasing reliance on space technologies. magnetosphere to be less governed by so- Most data gathered by satellites and lar wind dynamics and more governed by ground-based instruments are in the form the highly nonlinear internal dynamics. of time series. Time series information is In Figure 2, is shown the windowed analyzed nonparametrically to detect the signifi cance for the year 1974. Note that

73 1.0 1.0 Normalized Significance Normalized Significance 0.8 from Kp data from 1975 0.8 from Kp data from 1987 ) ) τ τ

0.6 0.6

S 0.4 SNL 0.4 NL Significance (S Significance (S 0.2 0.2 SL SL

0 0 0050 100 150 200 50100 150 200 Time Delay (τ) Time Delay (τ)

1.0 1.0 Normalized Significance Normalized Significance 0.8 from Kp data from 1980 0.8 from Kp data from 1990 ) ) τ τ

0.6 0.6

S 0.4 NL 0.4

SL SL Significance (S Significance (S 0.2 0.2 SNL

0 0 050 100 150 200 050 100 150 200 Time Delay (τ) Time Delay (τ)

Figure 1. The normalized linear and nonlinear signiﬁ cance, SL and SNL, obtained from the [Kp(t), Kp(t-τ)] embedding for two solar minima (1975 and 1987) and two solar maxima (1980 and 1990) as a function of time delay τ in hours. SL is obtained considering only second order cumulants while SNL is obtained including up to fourth order. It is obvious that for solar minimum there is a strong nonlinear response on the time scale of 40 hours, while for solar maximum there is a more linear response.

the signifi cance is often quite large, as it quasiperiodicity which is detectable only is computed for extended periods of time if nonlinear correlations are taken into (10-20 days). As such, the Kp time series account. As such one expects that linear should be reasonably predictable during models commonly used to predict mag- those periods. On the other hand, the netospheric response should be inaccu- evolution of the signifi cance indicates rate. Local-linear models (which include that the underlying dynamics are rather slow evolution of parameters) and non- variable; therefore, any predictive mod- linear models that fail to capture the in- el would need to be able to accommo- herent nonlinearity are also likely to fail date such changes in the underlying dy- where the dynamics suddenly change. namics. In this study, information-dynamical Self-Consistent Ion Cyclotron techniques to the Kp indices have been Heating in the Auroral Ionosphere applied. Using the cumulant-based sig- Recently, it has been demonstrated nifi cance, it has been established that that ion cyclotron waves excited in the the underlying dynamics of Kp evolu- auroral electron acceleration region could tion is, in general, nonlinear exhibiting a propagate into the ionosphere where they

74 500 while the oxygen density iterates more slowly. Although this is not a temporal 400 simulation, it would be natural to draw

300 the conclusion that helium fi rst bleeds off the ionosphere and when its density 200 is reduced suffi ciently, oxygen can be ef- Significance fi ciently heated. 100 In Figure 3 is shown the fi nal profi les for oxygen and helium. Note that 0 0 100 200 300 the energy increases in steps for the heli- Day of 1974 um profi le corresponding to peaks in the Figure 2. Signifi cance as a function of time heating rate which occur due to interfer- for Kp indices during 1974. An embed- ence of the refl ected wave from the iono- ding dimension 3 is used with a time lag sphere. Lower-frequency waves with lon- of one hour. All quantities were computed ger wavelength heat oxygen (which has a for a slicing window of 300 hours every fi ve lower gyrofrequency at a given altitude), hours. so there are no peaks in the oxygen heat- could heat ions that would then fl ow out ing rate at this altitude. of the ionosphere. As the ions fl ow up- It should be noted that the helium ions wards into the magnetosphere, the back- are heated signifi cantly more than the ox- ground densities are modifi ed. As the ygen because (a) absorption at the helium background profi les change, the wave resonance is more effi cient and (b) the propagation also changes signifi cantly be- helium absorption bleeds off wave ener- cause wave absorption depends critically gy that could potentially heat oxygen at on the minor ion concentrations. These lower altitudes. modifi cations to wave propagation and This result is in agreement with ob- absorption feed back on the out-fl owing servations shown in Figure 4 that show ions. helium heating dominates oxygen heat- In order to account for the coupling being for most observed ion cyclotron wave tween the waves and ions, we solve itera- events. The observations were considered tively. Based on the wave spectrum in the surprising because it was believed that auroral acceleration region, wave propa- oxygen heating would be more effi cient gation and absorption are computed as as the quasilinear heating rate scaled with a function of altitude. Monte Carlo test mass to a positive power. particle calculations are then performed to determine the ion distributions given Kinetic Ballooning Instabilities the wave heating rate. Moments of the for Substorm Onset distribution are used to compute an it- One of the key issues in space phys- erated plasma profi le, which then is used ics is understanding the physical mecha- for a new wave propagation calculation. nism that leads to violent disruptions of The process is iterated until a convergent the magnetosphere called substorms. The ion profi le is found. substorm onset is observed to be associ- It is found that after seven iterations ated with the growth of a low-frequen- the system has reached a limit cycle that cy instability that is observed in the late does not change signifi cantly. The helium substorm growth phase just prior to sub- density quickly attains its fi nal profi le, storm onset with a wave period of 50-75

75 0

80 Oxygen Energy ) Oxygen Density

E⊥ 60 1500km

EII tot 0.01 40 Ebeam Energy (eV)

20 Density (nn TII 0 0.001 2000 3000 4000 2000 3000 4000 Altitude (km) Altitude (km) 200 0

Helium Energy ) Helium Density 160 E⊥ 1500km 120 0.01 EII tot 80 Energy (eV) Density (nn 40 Ebeam

TII 0 0.001 2000 3000 4000 2000 3000 4000 Altitude (km) Altitude (km)

Figure 3. Energy and density profi les for oxygen and helium assuming a relative concentra- tion of 5% and 1% of the ambient plasma. Note the step-like heating of the helium and gradual heating of the oxygen. The bulk helium is heated more than oxygen. seconds. This low-frequency mode is also or magnetotail confi guration yield com- observed to persist during the substorm pletely different results. If nothing else, expansion phase, indicating that it plays these results have demonstrated the im- an important role in the depolarization portance of modeling the plasma com- process. The observed low-frequency instabil- 10,000 ity is identifi ed as the kinetic ballooning instability based on an analytical theo- 1,000 ry. However, numerical investigations of the ballooning instability have been per- 100 Maximum Energy formed only based on the ideal-MHD + He model using simplifi ed two-dimension- 10 al magnetic fi eld geometries and sim- 10 100 1,000 10,000 O+ Maximum Energy plifying assumptions about the plasma compressibility. It was found that the Figure 4. Observations of ion heating events associated with ion cyclotron wave ballooning stability depends critically are shown in green (Lund et al., 1998). on the equilibrium fi eld structure and Note that, in general, helium is heated more the assumptions concerning the plasma strongly than oxygen, consistent with the compressibility. Moreover, stability cal- model results. The open circles are heating culations based on different simplifying events that are not associated with ion cy- assumptions about the physical model clotron waves.

76 pressibility correctly and using realistic our three-dimensional equilibrium code. equilibrium ﬁ elds. Figures 5 and 6 show the color plot in Recently, three-dimensional numeri- the equatorial plane and contours in the cal equilibrium solutions of the magneto- northern polar ionosphere of the squared sphere during the substorm growth phase eigenfrequency (negative values indicate have been obtained, which includes a instability). strong cross-tail current sheet in the Also shown in Figure 5 are the con- near-Earth plasma sheet region. The bal- tours of the azimuthal current density looning instability is expected to be most and in Figure 6 is the color plot of the unstable in the cross-tail current sheet re- ﬁ eld-aligned current density. Note that

gion. The ideal-MHD eigenmode equa- all fi eld lines beyond X ≈ -6RE down tions have been derived without making the tail in the night side are unstable. assumptions about the plasma compress- The region of the most unstable modes ibility. Two equations describing the cou- tracks well with the strong cross-tail cur- pling between shear Alfvén-type modes rent sheet region, consistent with expec- and slow magnetosonic modes are ob- tations based on substorm onset obser- tained. The coupling occurs because of vations. The region of maximum growth terms involving magnetic fi eld curvature rate is located in the tailward side of the and plasma pressure. strong cross-tail current region. In the The coupled equations were simpli- polar ionosphere, the fi eld lines in the fi ed using the WKB-ballooning formal- peak ballooning instability growth rate ism and solved using standard variational region map to the transition region be- methods for a realistic three-dimensional tween the region-1 and region-2 cur- growth phase equilibrium obtained from rents. Although the ideal-MHD model

Figure 5. The square of ballooning-mode frequency (in mHz2) is shown in color in the equatorial plane with the full MHD model. The azimuthal current density (in nA/m2) contours are also plotted to show the location of the most unstable region relative to the strong cross- tail current region.

77 the maximum acceleration of the CME. On the other hand, in small fl ares that are not associated with CMEs, soft X- ray ejecta are often observed. In the pre- fl are phase, the rising motion of an X- ray ejecta is rather slow, but it is highly accelerated in the fl are impulsive phase, in which hard X-ray emission is detected. It is generally accepted that both CMEs and small-scale X-ray ejecta contain a magnetic fl ux rope structure. But what Figure 6. The contours of the square of physical connection lies between the fl are ballooning-mode frequency (in mHz2) are plotted over the northern polar ionosphere energy release and the fl ux rope acceler- for the full MHD model. The fi eld-aligned ation? current density (in color) is plotted to show The investigation is based on resistive that the most unstable ballooning instabil- MHD simulations of a magnetic arcade ity region is located at the transition region undergoing fi eld line footpoint shearing between the region-1 and region-2 cur- and magnetic reconnection under non- rents. uniform resistivity. When the magnetic shear exceeds a critical value, a fl ux rope over estimates the instability growth rate is generated by magnetic reconnection of due to the lack of particle kinetic effects, line-tied arcade fi elds. By a continuing the results show the fi eld lines where the shearing process, another fl ux rope can ballooning free energy is largest and the be created in the lower-lying arcade. The most unstable ballooning mode is locat- new fl ux rope, attracted by the upper ed. Including the particle kinetic effects, one, is accelerated upward and the two the unstable region is expected to be refl ux ropes merge by magnetic reconnec- duced to in the strong cross-tail current tion. During the fast upward motion of sheet region mainly, consistent with sub- the new fl ux rope and the integrated one, storm observations. the arcade fi eld lines below form a very thin current sheet, where a fast magnet- Flux Rope Acceleration ic reconnection is induced. This mag- and Enhanced Magnetic netic reconnection endows the fl ux rope Reconnection in Solar Flares above with momentum and magnetic A solar fl are is intense, abrupt release fl ux. Consequently, the fl ux rope is fur- of energy in the low solar corona. Coro- ther accelerated, and this again facilitates nal mass ejections (CMEs), another type enhancement of magnetic reconnection. of grand-scale solar eruptive phenome- These sequential feedback processes can na, are often accompanied by major X- be repeated as long as the active region ray fl ares. Recent studies have revealed is replenished with magnetic shear. There that rapid acceleration of a CME in the are a total of four fl aring (reconnection) low corona is associated with the fl are rise events in our simulation run. phase. The most intense peak in hard X- The MHD modeling results show that rays (≥25 keV) observed by the Reuven the fl ux rope acceleration rate and the en- Ramaty High Energy Solar Spectroscop- hanced reconnection rate in the current ic Imager (RHESSI) occurs at the time of sheet under the new fl ux rope rely cru-

78 cially on the dependence of the anom- vember 24, 2000, X1.8 (large) X-ray fl are alous resistivity on the current densi- (see Figure 7). With realistic physical pa- ty. With a quadratic dependence of the rameters employed, the height, speed, anomalous resistivity on the current den- and acceleration profi les of the mod- sity, the modeling results agree well with el fl ux rope match well with the corre- X-ray observations of two specifi c fl are sponding time profi les of the observed events. fi lament (in the lower corona) and CME The simulation results of a fast recon- (in the upper corona). The maximum re- nection event were fi rst compared with connection rate of the model occurs al- the fl are-CME observations of the No- most coincidently with the observed

Figure 7. The solid curves in the top three panels show the time profi les of the height (from the solar limb), speed, and acceleration of the erupting fi lament in the low corona and the coronal mass ejection in the outer corona associated with the November 24, 2000, X1.8 fl are. The dotted curves in the top three panels show the respective time profi les of the model fl ux rope. The solid curve in the fourth panel shows the corresponding GOES X-ray fl ux, and the dotted curve in the fi fth panel shows the reconnection electric fi eld in the model.

79 peak CME acceleration and impulsive ray emission. In this case also, the simu- hard X-ray emission, which occur dur- lation result agrees well with the observed ing the rise phase of the observed GOES time profi le of the ejecta. satellite X-ray profi le. The reconnection These two encouraging quantitative electric fi eld in the model is as large as comparisons support the fl are model, in 1000 V/m, which is way above the Dreic- which the magnetic reconnection and er electric fi eld of ~10-2 V/m. With that the fl ux rope acceleration exert a feed- fi eld-aligned electric fi eld, electrons can back effect to each other, and nonuni- be accelerated to 103 keV in a fi eld- form, anomalous resistivity plays a cru- aligned distance of mere one kilometer. cial role in determining the reconnection Also compared are the result of a slow- rate and fl ux rope acceleration rate. Also er reconnection event with the Yohkoh it strongly suggests that the fl are X-ray observation of the November 11, 1993, emission is generated by electrons accel- C9.7 (smaller) X-ray fl are, which showed erated along fi eld lines by the reconnec- soft X-ray ejecta acceleration and hard X- tion electric fi eld.

80 Basic and Applied Physics Experiments

he Princeton Plasma Physics which could improve satellite communica- (PPPL) has an active program in tion systems. T Basic and Applied Plasma Physics which supports the Laboratory’s mission Hall Thruster Experiment to create new knowledge in plasma sci- A Hall Thruster is a plasma-based pro- ence and to use this knowledge to develop pulsion system for space vehicles. The new plasma technologies. These projects vast majority of satellites worldwide have generally consist of small experiments relied on chemical thrusters. The amount focused on a specifi c topic of interest. All of fuel that must be carried on board by of these projects have strong graduate and a satellite depends on the speed that the undergraduate participation, and many of thruster is able to eject it. Chemical rock- them have ties to work being done in the ets have very limited fuel exhaust speed. PPPL Theory and Advanced Simulations Plasmas can be ejected at much high- Department. er speeds, therefore less fuel need be car- Some of these basic physics experiments ried by the satellite. Until recently, the lie at the frontiers of fusion research. For Hall Thruster approach had been pur- example, the novel Field-reversed Con- sued most vigorously in Russia; during fi guration experiment is designed to create the past twenty years, the Russians placed a remarkably effi cient magnetic confi ne- about 100 Hall Thrusters in orbit. ment system which could eventually be In FY99, a Hall Thruster Experiment used to burn advanced fusion fuels, while was established at the Princeton Plasma the heavy ion fusion research aims to cre- Physics Laboratory (PPPL). The PPPL ate and focus extremely high-intensity effort was the result of a collaborative ion beams onto an inertial fusion target. theoretical research effort with the Cen- These and all the other small experiments ter for Technological Innovation at Ho- are strongly coupled to plasma physics lon, Israel. This study, initially funded research at other national laboratories and by the U.S. Air Force Offi ce of Scientifi c universities. Research (AFOSR), identifi ed improve- These experiments also have an im- ments that might make Hall Thrust- portant role in creating links between ers more attractive for commercial and plasma physics and other areas of science military applications. After demonstrat- and technology. For example, the work ing state-of-the-art thruster operation, on high-intensity accelerators is directly including decreased plasma plume, the applicable to future experiments in high project acquired broader support. In ad- energy physics, and the Hall Thruster Ex- dition to support from AFOSR, the pro- periment may develop into a technology gram now enjoys support from the De-

81 fense Advanced Research Projects Agency Magnetic Circuit Cathode-neutralizer (DARPA), the New Jersey Commission on Science and Technology, and the U.S. Department of Energy. The facility is pic- tured in Figure 1. B Hall Thruster Operation A conventional ion thruster consists of IH E two grids, an anode and a cathode, be- Anode tween which a voltage drop occurs. Pos- (Gas Distributor) Plasma Jet itively charged ions accelerate away from the anode toward the cathode grid and Figure 2. The Hall Thruster concept. through it. After the ions get past the cathode, electrons are added to the fl ow, the space between the grids, limiting the neutralizing the output. A thrust is exert- ion fl ow and, therefore, the magnitude of ed on the anode-cathode system, in a di- the thrust that can be attained. rection opposite to that of the fl ow. Un- In a Hall Thruster, electrons inject- fortunately, a positive charge builds up in ed into a radial magnetic fi eld neutralize the space charge. The magnitude of the fi eld is approximately 200 gauss, strong enough to trap the electrons by causing them to spiral around the fi eld lines. The magnetic fi eld and a trapped-electron cloud together serve as a virtual cathode (Figure 2). The ions, too heavy to be affected by the fi eld, pass through the virtual cathode. The movement of the positive and negative electrical charges through the system results in a net force on the thruster in a direction opposite that of the ion fl ow. Plasma thrusters for present-day space applications generally employ xenon propellant. Xenon is relatively easy to ionize and store on board the spacecraft. It also has a high atomic number (54), which means a lot of mass per ionization energy expended. The ionization energy is an unavoidable ineffi - ciency. In the range of exhaust velocities most useful for present-day space applications, about 15 km/sec, the energy loss for once-ionized xenon is less than 10 percent of the exhaust energy. (If the Figure 1. The PPPL Hall Thruster Experi- weight per atom were half, this percent- ment and research team. age would double.)

82 Hall Thruster Applications One of the interesting observations made Thrusters are used to compensate for in FY03 was an ion focusing effect. atmospheric drag on satellites in low- In addition to imagining larger and earth orbit, to reposition satellites in geo- more powerful thrusters capable of ac- synchronous orbit, or to raise a satellite celerating satellites more quickly or pow- from a lower orbit to geosynchronous or- ering larger satellites, scientists also envi- bit. As a rule of thumb, for each kilogram sion a large satellite disbursing hundreds of satellite mass, one or two watts of on- of the smaller ones for the exploration board power must be made available. of a planet or as a spaced-based radar ar- PPPL has a medium-size Hall Thruster, ray. The Hall Thruster may be too power which consumes several hundred watts of hungry for this application, but answers power, making it suitable for a satellite to these and other questions may emerge with a mass in the range of a few hun- from research underway at PPPL. dred kilograms. PPPL physicists are now developing for AFOSR and for DARPA such small- Hall Thruster Results er thrusters, or “Hall micro-thrusters,” An important facility upgrade oc- which operate with power outputs in curred in FY02: the PPPL Hall Thrust- the 100-watt range, useful for very small er facility was equipped with cryopumps, satellites with masses of 50 to 100 kilo- making possible experiments with pow- grams. The scaling to low power is by no er levels higher than the sub-kW levels means straightforward, as the power den- previously employed; PPPL researchers sity tends to grow at small sizes, just as can now operate a segmented electrode the smaller feature sizes are more suscep- Hall Thruster at greater than 2 kW. The tible to heat loading. In attacking these cryopumps also produce a cleaner vac- technological constraints, PPPL scien- uum, so surface-sensitive effects can be tists proposed and are now developing a better explored. New diagnostics were in- cylindrical variation of the Hall Thruster stalled in FY03 to explore both the chan- in which the central magnetic pole is al- nel and the plume physics. most eliminated (Figures 3 and 4). In the last year, key advances were In the last year, using unique plas- made both for medium-power thrust- ma diagnostics inside the micro-thrusters and for low-power thrusters. By seg- er channel, several interesting phenome- menting the channel of a medium-pow- na were discovered, including a density er Hall Thruster, with each segment held peak near the thruster axis. Understand- at a speciﬁ c electric potential, research- ing and further exploring these phenom- ers at PPPL were able to control exactly ena is an ongoing part of the PPPL mi- where the voltage drop occurs along the cro-thruster program. length of the thruster. In some regimes, this has been used to decrease the plume Magnetic Nozzle Experiment divergence. A small plume divergence is The Magnetic Nozzle Experiment a very important design feature for Hall (MNX) studies the properties of magne- thrusters for facilitating spacecraft inte- tized linear plasmas expanding through gration. At PPPL, detailed measurements regions of converging and diverging mag- of the electric potential in the interior of netic ﬁ eld lines. During FY03, experi- the Hall thruster were carried out and re- ments were also performed on plasmas lated to changes in the plume divergence. expanding through mechanical (materi-

83 Figure 3. Schematic of the cylindrical Hall Figure 4. The 2.6-cm-diameter cylindrical Thruster. Hall Thruster. al) nozzles. In both confi gurations, nov- seen to accelerate from their thermal en- el atomic and plasma physics phenome- ergy, approximately 0.4 eV, to the son- na occurred. The result of most relevance ic value, Ei ~ Te ~ 7 eV, at the entrance to spacecraft-propulsion applications was to the mechanical aperture. As the Ar+* the acceleration of argon (Ar) plasma ions ions fl owed beyond a mechanical aper- to a specifi c impulse of 1,400 seconds, a ture positioned upstream of the magnet- 40% improvement over the maximum ic nozzle, their energy increased to more observed during the previous year. than 60 eV. With the mechanical aper- Ion speed measurements were per- ture downstream of the nozzle, increase formed with a laser-induced fl uores- of the (upstream) nozzle magnetic fi eld cence (LIF) diagnostic, procured under increased the LIF signal but reduced the a U.S. Department of Energy (DOE) argon ion energy (Figure 5). This behav- contract and loaned to PPPL by Pro- ior is consistent with magnetic-mirror fessor Earl Scime of West Virginia Uni- refl ection of high perpendicular-energy versity (WVU). Mr. Xuan Sun, a WVU electrons formed by the helicon plasma- graduate student, participated extensive- heating system. ly in the experiments and theoretical in- One of the surprising atomic phys- terpretation of the results. The LIF sys- ics phenomena observed was an asym- tem uses a compact, tunable, 15-mW metry to the +σ and -σ Zeeman peaks solid-state-diode laser to excite meta- of the supersonic ions observed in the stable argon (Ar+*) ions in the plasma. expansion region. This asymmetry, up Fluorescence from Ar+* was detected in to a factor of three, was seen to depend both the main chamber and the expan- most strongly on the nozzle magnetic sion region and on both sides of mechan- fi eld strength. Through a series of exper- ical apertures positioned co-axial to the iments and theoretical analyses, this ef- plasma fl ow. With the mechanical aper- fect was explained as the optical pump- ture in the main chamber, the ions were ing of upstream meta stable argon ions

84 70 RMF were performed at the 10-kW pow- Ion Energy er level at axial magnetic ﬁ eld strengths 60 near 100 G. The RMF was able to break

50 down the helium gas pre-fi ll with no pre- ionization and to sustain discharges for 40 times exceeding 1 ms. Plasma density, measured with both 35-GHz and 170- 30 GHz interferometers, reached 1012 cm-3. LIF Amplitude The electron temperature, inferred from 20 a collisional-radiative model for helium- Argon Ion Energy (eV), LIF Amp (arb.) 10 line ratios, exceeded 20 eV. From spec- 0 500 1000 1500 2000 2500 tral measurements, plasma contamina- Nozzle Magnetic Field Strength (G) tion was less than 1%. Figure 5. The dependence of ion energy Theoretical studies of ion dynamics and ion density [laser-induced fl uorescence in FRCs using Hamiltonian and sym- (LIF) amplitude] on the nozzle magnet- plectic techniques continued in collab- ic fi eld measured at a position 4 cm down- orations with A. Glasser of Los Alamos stream of the magnetic nozzle. The strength of the Helmholtz axial fi eld was ~600 G in National Laboratory and G. Zaslavsky the main chamber. of the Courant Institute for Mathemati- cal Sciences, New York University. A paper, to appear in Physics of Plasmas, gave by the counter propagating laser beam. a detailed classifi cation of orbit shapes This effect is important to the determi- and looked at the adiabatic limit that re- nation of plasma density from LIF am- sults for highly elongated FRC devic- plitude. es, thereby establishing a criterion for separatrix crossing which leads to adia- FRC/RMF Experiment batic chaos. A second paper, to appear The Field-reversed Confi guration/Ro- in Communications in Nonlinear Sci- tating Magnetic Fields (FRC/RMF) ex- ence and Numerical Simulation, applied periment is designed to study the effects a novel averaging scheme for the radi- of odd-parity rotating magnetic fi elds al and axial Hamiltonians to derive con-

(RMFo) on magnetized plasmas. The ex- ditions for resonance and incipient sto- periment was fi rst motivated by the pre- chasticity. The Chirikov criterion was diction that odd-parity RMF would then applied to fi nd conditions for the maintain the closed fi eld lines of the fi eld- transition to strong chaos. reversed confi guration and hence would Figure 6 shows a Poincaré plot for improve energy confi nement compared ions in a spherical FRC without RFM. to conventional even-parity rotamaks. The dimensionless energy and azimuth- The second motivation was the theoreti- al canonical momentum are set to 0.063 cal prediction that RMF in the ion-cyclo- and 0.258, respectively. Nonlinear reso- tron-range-of-frequencies (ICRF) would nance for fi gure-8 orbits are clearly seen heat ions and electrons to thermonuclear as necklaces of islands, bounded by Kol- energies by a stochastic heating process. mogorov-Arnold-Mosher (KAM) sur- In FY03, experiments on plasma pro- faces. Lowering either the canonical duction and sustainment by odd-parity azimuthal momentum or the FRC elon-

85 0.5 • coherent electromagnetic radiation FRC Surface-of-section Taken at z = 0 generation, including free electron lasers, cyclotron masers, and mag- netrons; • advanced accelerator concepts with 0 high-acceleration gradients; and • investigation of nonlinear collective Radial Velocity (Radial Velocity r ) processes and chaotic particle dynamics in high-intensity charged- 0.5 particle beams. 0.3 0.5 0.7 0.9 1.1 Normalized Radius Research on nonneutral plasmas and high-intensity accelerators at PPPL fo- Figure 6. Poincaré plot of ion dynamics in a spherical fi eld-reversed confi guration with- cuses on three areas: out rotating magnetic fi eld. • basic experimental investigations of nonneutral plasmas confi ned in a gation would result in greater chaos, i.e., Paul trap with oscillatory wall volt- disappearance of the KAM surfaces. ages, used to simulate intense beam propagation through a periodic Nonneutral Plasmas and quad ru pole fi eld confi guration; High-intensity Accelerators • analytical and numerical studies of A nonneutral plasma is a many-body the nonlinear dynamics and collec- collection of charged particles in which tive processes in intense nonneu- there is not overall charge neutrality. Such tral beams propagating in periodic- systems are characterized by intense self- focusing accelerators and transport electric fi elds and, in high-current confi g- systems, with particular emphasis urations, by intense self-magnetic fi elds. on next-generation accelerators for Nonneutral plasmas, like electrically neu- heavy ion fusion, spallation neutron tral plasmas, exhibit a broad range of col- sources, and high-energy physics ap- lective properties, such as plasma waves plications; and and instabilities. The intense self-fi elds in a nonneutral plasma can have a large in- • experimental investigations of ra- fl uence on detailed plasma equilibrium, dio-frequency plasma sources for stability, and confi nement properties, as beam space-charge neutralization, well as on the nonlinear dynamics of the experimental and theoretical studies system. of multielectron loss events, and op- There are many practical applications timization of negative ion beams for of nonneutral plasmas. These include: heavy ion fusion drivers. Paul Trap Simulator Experiment • improved atomic clocks; The Paul Trap Simulator Experi- • positron and antiproton ion sources; ment (PTSX) is a compact experiment that simulates intense beam propagation • antimatter plasmas, with applica- through periodic focusing magnetic al- tion to antihydrogen production; ternating-gradient transport systems over

86 distances of kilometers. The simulation is forming intense beam propagation ex- possible because the transverse dynamics periments in long alternating-gradient of the particles is equivalent in the PTSX transport systems. and the periodic focusing magnetic alternating-gradient transport systems. High-intensity Accelerators Planned experimental studies include Temperature anisotropies that develop investigations of beam mismatch and en- naturally in accelerators during the accel- velope instabilities, collective wave ex- eration phase may provide the free en- citations, chaotic particle dynamics and ergy to drive a Harris-type instability in production of halo particles, and mech- intense particle beams and lead to a dete- anisms for emittance growth. The PTSX rioration of beam quality. For example, if linear Paul trap confi nes cesium ions in the nonlinear response of the beam parti- the transverse plane by applying oscillato- cles is to develop a suffi ciently large axial ry voltages to the four quadrants of a 2-m velocity spread, this may provide a limit long, 40-cm diameter, segmented prima- on the minimum spot size achievable in ry cylinder. Applied static voltages on the heavy ion fusion experiments. To deter- 40-cm long end cylinders provide axial mine the linear and nonlinear dynamics confi nement. The temporal frequency of of the temperature anisotropy instabili- the oscillating voltage in the PTSX cor- ty in intense beams, the Beam Equilibri- responds to the spatial frequency of the um Stability and Transport (BEST) code magnets in the actual transport system. has been used to determine the detailed In FY03, the PTSX demonstrated the three-dimensional (3-D) stability prop- ability to simulate beams with normal- erties over a wide range of temperature ized intensities of up to 80%. Further- anisotropy and beam intensity. The low- more, the data in Figure 7 shows that the noise feature of the nonlinear delta-f sim- plasma can be confi ned, relatively un- ulations permits a thorough characteriza- changed, for hundreds of milliseconds. tion of the instability growth rate, mode This corresponds to equivalent propa- structure, and nonlinear saturation mech- gation distances of tens of kilometers. anism. It is found in the case of extreme These achievements show that the PTSX temperature anisotropy that the beam is is a fl exible, low-cost alternative to per- stable at low-to-moderate intensities, but

3 (a) t = 3 ms (b) t = 32 ms (c) t = 316 ms

1 Charge (pC) 0 -10 -5 0 5 10 -10 -5 0 5 10 -10 -5 0 510 Radius (cm) Radius (cm) Radius (cm)

Figure 7. The radial proﬁ le of a moderate-intensity trapped plasma (normalized intensity of 18%) changes only slightly after 316 ms. For the parameters in this experiment, this corresponds to more than 20 km of equivalent beam propagation.

87 can exhibit a strong Harris-type insta- κ κ 2 a(s,z)/a(0,z) b(s,z)/a(0,z) q(s)/ bility for larger space-charge intensities. 0 Moreover, the instability saturates non- -2 linearly through the development of an 0 25 50 75 100 125 150 axial velocity spread and resonant wave- 2 a(0,z) = 11.2 mm b(0,z) = 6.4 mm particle interactions (Landau damping) 0 -2 by the tail ions. Detailed stability prop- 175 200 225 250 275 300 325 erties have been calculated for azimuth- 2 z/zb(s) = 0.96 al mode excitations m = 0, 1, 2, 3, re- 0 -2 vealing that the dipole mode excitation 350 375 400 425 450 475 500 (m = 1) is the most unstable mode. Fi- 6 4 nally, the ranges of temperature anisotro- 2 0 py and beam intensity corresponding to -2 502 504 506 508 510 512 514 516 stable (quiescent) beam propagation have s (m) been determined. In the presently envisioned confi gu- Figure 8. Beam envelope dynamics during the drift compression and fi nal focus for a rations for heavy ion fusion, it is neces- typical heavy ion fusion beam. The shown sary to longitudinally compress the beam envelope dynamics are for a beam slice near bunches by a large factor after the accel- the front end of the charge bunch. eration phase. Because the space-charge force increases as the beam is compressed, a larger focusing force is needed to confi ne many accelerator applications. To study the beam in the transverse direction. It is the range of validity of both the Born necessary to have a non-periodic quadru- approximation and the classical trajec- pole lattice along the beam path. Recent- tory calculation, theoretical and experi- ly, an innovative design concept for such mental investigations of the stripping of a focusing lattice has been developed us- more than 18 different pairs of projectile ing the transverse envelope equations for and target particles in the range of 3-38 an intense charged-particle beam. Four MeV/amu have been done. In most cases, time-dependent magnets are introduced both approximations give similar results. in the region upstream of drift compres- However, for fast projectile velocities and sion to focus the entire beam pulse onto low ionization potentials, the classical ap- the same focal spot. Drift compression proach is not valid and can overestimate and fi nal focusing schemes have been de- the stripping cross sections by neutral at- veloped for a typical heavy ion fusion oms by an order-of-magnitude. When driver and for the Integrated Beam Ex- experimental data and theoretical cal- periment (IBX) presently being designed culations are not available, approximate by the Heavy Ion Fusion Virtual Nation- formulas are frequently used. Based on al Laboratory. Shown in Figure 8 are the experimental data and theoretical pre- beam envelope dynamics during the drift dictions, a new fi t formula for ionization compression and fi nal focus together cross sections by fully stripped ions has with the non-periodic lattice and four fi - been proposed. The resulting plots of the nal focus magnets for a typical heavy ion scaled ionization cross sections of hydro- fusion beam. gen by fully stripped ions are shown in Knowledge of ion-atom ionization Figure 9. The new fi t formula was also cross sections is of great importance for applied to the ionization cross sections

88 Charge Neutralization Experiments (a) Heavy ion fusion research has developed reactor design concepts requiring multiple heavy ion beams to be focused to small spot size (millimeter-scale) in the 0.1 target chamber. The Neutralized Trans- port Experiment (NTX) at the Lawrence Cross Section Berkeley National Laboratory is investigating the most promising charge neutralization methods to achieve this level 110of focusing. One neutralization approach Velocity utilizes large-volume plasma to charge 1 (b) neutralize the heavy ion beam. The charge neutralization process has been modeled theoretically as a heavy ion beam pulse propagating through a highly ionized cylindrical plasma column. The background 0.1 plasma ion motion is neglected, and electrons from the background plasma move Scaled Cross Section into the ion beam channel, reducing the net positive beam space charge over the 1 10 Scaled Velocity larger volume of the plasma channel. Ion Figure 9. Ionization cross sections of hy- beam densities are expected to be in the 10 11 -3 drogen by fully stripped ions of hydrogen range of 10 -10 cm . Present calcu- (squares), helium (circles), lithium (over- lations require the plasma to exceed one turned triangles), and carbon (triangles) as meter in length with an electron density a function of projectile velocity in atomic in the range of 1 to 100 times the beam units of (a) experimental data and (b) the density. same data scaled according to the new ﬁ t PPPL researchers have developed plas- formula. ma sources to support the charge neutralization studies conducted on the NTX. of helium. Again, all of the experimental In some regimes of operation, the sourc- and theoretical results merged close to- es are well characterized and have been gether on the scaled plot. applied to plasma processing of semicon- Presently, there are many other re- ductor devices. One of the plasma sourc- search activities in the high-intensity ac- es developed at PPPL is a radio-frequen- celerator area. For example, in a recent cy plasma source that operates at 13.6 calculation using the Vlasov-Maxwell MHz. For radio-frequency waves, the equations, the classical resistive-wall in- skin depth is on the order of one centi- stability has been extended to the cases meter. Therefore, the radio-frequency of arbitrary azimuthal mode number and antenna is placed as close as possible to arbitrary space-charge intensity. Studies the interaction-region with the ion beam. in the high-intensity accelerator area are Operating in a pulsed mode, the source is providing valuable guidance in the de- able to produce plasma densities exceed- sign and planning of future accelerator ing 1011 cm-3 at background gas pres- experiments. sures in the few microTorr range.

89 The radio-frequency plasma source ber medium, neutrals should reduce the was installed on NTX (Figure 10) and beam space-charge-expansion. Halogens’ collaborative experiments are being car- large electron afﬁ nities make them the ried out to determine the effectiveness best candidates for high brightness neg- of background plasma in neutralizing ative ion sources. the ion beam space charge. Initial results PPPL recently joined with research- look promising, as beams with initial ra- ers at Lawrence Berkeley National Lab- dii of centimeters are successfully focused oratory (LBNL) and the Virtual Nation- down to a few millimeters after passing al Laboratory for Heavy Ion Fusion to through a neutralizing plasma. conduct a proof-of-concept experiment at LBNL using chlorine in a radio-fre- Negative Ion Driver Beams quency-driven ion source. Without in- for Heavy Ion Fusion troducing any cesium (which is required Inertial conﬁ nement fusion concepts to enhance negative ion production in employing heavy ion beam drivers have hydrogen ion sources), a negative chlo- traditionally assumed the use of posi- rine current density of 45 mA/cm2 was tively charged ions. However, negative obtained under the same conditions that ions have recently attracted interest af- gave 53 mA/cm2 of positive chlorine. ter a feasibility study by PPPL research- This suggests the presence of nearly as ers suggested that modest extrapolations many negative ions as positive ions in the of existing technologies might result in a plasma near the extraction plane. The viable alternative. Unlike positive ions, negative ion spectrum was 99.5% atomic negative ions will not collect electrons chlorine ions, with only 0.5% molecular from surfaces they pass, which changes chlorine, and essentially no impurities. their focusing characteristics, and nega- Even without the electron suppression tive ions can readily be converted to neu- technology used in negative hydrogen tral atoms by laser photodetachment as extraction, the ratio of co-extracted elec- they enter the target chamber. Although trons to negative chlorine ions was as low they will be ionized in crossing the cham- as 7 to 1, much lower than the ratio of their mobilities, suggesting few electrons in the near-extractor plasma. This, along with the near-equivalence of the positive and negative ion currents, suggests that the plasma in this region was mostly an ion-ion plasma. Planning is presently underway for a follow-up experiment to be conducted on a test stand at the Lawrence Liver- more National Laboratory, where higher radio-frequency power capability will allow the observed linear current densi- Figure 10. PPPL researchers Andy Carpe (left) and Erik Gilson visit the Lawrence ty scaling to be followed to higher levels, Berkeley National Laboratory to prepare a along with a test of a multiple-beamlet radio-frequency plasma source for installa- negative chlorine ion source, and direct tion on the Neutralized Transport Experi- comparisons of positive and negative ment (NTX). ion beam emittance (optical quality)

90 with a more sophisticated measurement system.

Diagnostic Development Electron-Bernstein Wave Emission Diagnostic Spherical torus (ST) and other magnetically confi ned plasmas that operate at relatively high plasma densities and low-confi ning magnetic fi elds cannot use conventional electron cyclotron emission (ECE) electron temperature diagnostics. In these “overdense” plasmas, mode-converted electron-Bernstein wave (EBW) emission may be used as an electron temperature profi le diagnostic with similar Figure 11. The NSTX electron-Bernstein temporal and radial resolution to a con- wave radiometer. ventional ECE diagnostic. The key to developing a viable EBW electron tem- 3-D Microwave Imaging Diagnostic perature diagnostic is to characterize and The 3-D imaging diagnostic system control the mode-conversion effi cien- consists of a combined Microwave Imag- cy of EBWs to electromagnetic waves. ing Refl ectometer (MIR) and an Electron This conversion generally occurs near Cyclotron Emission Imaging radiometer the plasma edge of these overdense plas- (ECEI) for plasma fl uctuation measure- mas. Once the EBW emission is mode- ments. The diagnostic utilizes large op- converted it can be measured by a micro- tics to simultaneously collect launched wave radiometer. microwaves refl ected from the cut-off Recent EBW radiometer research on layer and intrinsic electron cyclotron mi- PPPL’s Current Drive Experiment-Up- crowave emission. This is in contrast to grade (CDX-U) ST has demonstrated conventional systems, which employ controlled mode conversion of EBWs to small waveguides to collect the signals. extraordinary mode, electromagnetic ra- The goal of this 3-D imaging system is diation using a local limiter at effi cien- a simultaneous measurement of fl uctua- cies near 100%. As a result, the electron tions of density and temperature within temperature profi le was measured. The the focal depth of the designed imaging potential for measuring the plasma in- system. ternal magnetic profi le using the mode- It has been demonstrated theoretical- converted EBW emission spectrum was ly and in laboratory tests that the MIR also demonstrated. During FY03, an system potentially provides signifi cantly EBW diagnostic, designed based on the more accurate characterizations of densi- CDX-U EBW emission research, was in- ty fl uctuations compared with the con- stalled on the National Spherical Torus ventional systems. It will also provide a Experiment (NSTX) to demonstrate this unique opportunity to measure poloidal diagnostic technique on a larger ST plas- wavenumbers (16 channels) of density ma and to contribute to the NSTX plas- fl uctuations simultaneously. The ECEI ma physics program (Figure 11). system is also a multichannel ‘imaging’

91 system consisting of 128 (16 poloidal by efforts concentrated on absolute cali- 8 radial) channels. bration of the system and on successful PPPL worked with researchers from two-dimensional imaging of MHD-lev- the University of California at Davis el temperature perturbations, before at- (UC Davis) and the FOM Institute for tempting to image random temperature Plasma Physics in the Netherlands to fl uctuations. complete the design and fabrication of the MIR system culminating with in- X-ray Spectroscopy for NSTX stallation on the TEXTOR tokamak in A new type of a high-resolution X- Jülich, Germany, in fi scal year 2003. ray imaging crystal spectrometer was in- Debugging and initial operation of this stalled at NSTX for the experimental system during FY03 demonstrated that campaign in FY03 to measure ion and the signal level was suitable for analy- electron temperature profi les from spa- sis as indicated by the quadrature sig- tially resolved spectra of helium-like ar- nals shown in Figure 12. The high sig- gon, ArXVII. This instrument does not nal level of the MIR system, due to the require the injection of a neutral beam, newly developed, sensitive hybrid de- making it particularly valuable for diag- tector array provided by the UC Davis nosing radio-frequency-heated plasmas. team, permitted use of a simple beam It consists of a spherically bent quartz splitter for the ECEI system instead of crystal and a 10-cm by 30-cm two-di- an alternate and more diffi cult dichroic mensional position sensitive multi-wire plate design. In the ECEI system, FY03 proportional counter and it creates a de-

Discharge 93064 Channel 1 Channel 2 Channel 3 Channel 4 40 5 4 20 0 0 0 0 -20 -5 -40 -40 -4 -5 0 5 -404 -40 040 -40 0 40 Channel 5 Channel 6 Channel 7 Channel 8 40 1 40 20 0 0 0 0 -40 -40 -1 -20 -200 20 40 -10 1-40 0020 40 -20 Channel 9 Channel 10 Channel 11 Channel 12 10 40 40 40 0 20 0 0 0 -10 -20 -40 -40 -400 40 -400 40 -100 10-20 0 20 40 Channel 13 Channel 14 Channel 15 Channel 16 40 40 20 5 0 0 0 0 -40 -40 -5 -20 -400 40 -400 40 -50 5 -200 20

Figure 12 Quadrature signals from the microwave imaging reﬂ ectometer multichannel detector array.

92 magniﬁ ed image of a 80-cm-high plas- Because of the early termination of the ma cross section onto the detector. The NSTX experimental campaign in FY03, spatial resolution in the plasma is about the spectrometer was reinstalled on the one centimeter and is solely determined Alcator C-Mod tokamak where the ﬁ rst by the height of the crystal, its radius of proof-of-principle experiments were per- curvature, and the Bragg angle. The de- formed in June-July 2003. Figure 13 tector and data acquisition system were shows a spatially resolved spectrum of developed by Dr. S.G. Lee at the Korea ArXVII obtained from ohmically heat- Basic Science Institute for the X-ray crys- ed Alcator C-Mod plasma discharges. tal spectrometers on the Korea Super- The experimental data from the Alcator conducting Tokamak Advanced Research C-Mod will now be analyzed and the (KSTAR) device. The X-ray crystal spec- spectrometer will be reinstalled on NSTX trometers were designed in collaboration for the FY04 experimental campaign. with PPPL. The experimental results ob- In 2003, the analysis of argon spec- tained from NSTX experiments, or from tra, which were obtained from previ- other devices, are therefore also a valu- ous NSTX experimental campaigns, was able test of the X-ray crystal spectrome- completed. The analysis of these spec- ter design for KSTAR. tra revealed an inconsistency in the the-

Discharges: 101503 and 101703; Time: 0.320 - 0.700 s 500 w n=3 satellites xyq r a kz,j

400

300

15.8 Y (Channel Numbers) Y 31.6 49.7 200 83.6 113. 142. 162.

100 100 200 300 400 500 X (Channel Numbers) Figure 13. Spatially resolved contour plot spectrum of ArXVII accumulated from two very similar, ohmically heated, Alcator C-mod plasma discharges. The spectrum consists of the helium-like lines w, x, y, and z of ArXVII and the associated n = 2 and n = 3 satellites. Due to the different experimental arrangement of the spectrometer at Alcator C-mod, the spectrum represents a 1:1 image of the plasma. The shadows in the horizontal direction are caused by the 2-mm-wide supporting ribs on the beryllium entrance window of the detector. The separation between adjacent ribs is 1 cm. Color numbers indicate contour values.

93 oretical predictions for the n = 2 and n restoring forces for a surface wave. When = 3 dielectronic satellites in the wide- a liquid metal is subjected to a magnet- ly used atomic modeling code of Vain- ic and/or electric fi eld, the Lorentz force shtein and Safronova. This inconsisten- adds to the wave complexity, leading to cy was removed in new atomic modeling possible new instabilities. In the experi- calculations by M.F. Gu. These improved ment, an external wave driver with vary- calculations are in agreement with the ing frequency and amplitude is used to observed spectral data, and the derived excite surface waves in the liquid metal. electron temperature values are also in Reference cases are established using wa- good agreement with the central electron ter and gallium without magnetic and temperature values measured by Thom- electric fi elds. MHD effects can be ex- son scattering. The results from NSTX amined by imposing an external mag- are also of interest for the interpretation netic fi eld and/or electric current with of astrophysical spectra. varying amplitudes and angles with respect to wave propagation direction. A Liquid Metal Experiment laser refl ection system combined with A small-scale laboratory experiment at a gated ICCD camera is used to mea- PPPL is studying the fundamental phys- sure dispersion relation and wave ampli- ics of magnetohydrodynamic (MHD) ef- tudes. fects on surface waves and turbulence in It is found that the driven waves are liquid metal. MHD turbulence has been not affected by a magnetic fi eld applied regarded as an essential element of many in the perpendicular direction of wave intriguing phenomena observed in space propagation, while the waves are damped and laboratory plasmas, and it has been with a parallel magnetic fi eld. A linear a primary subject of basic plasma phys- theory, which takes into account MHD ics research. Recent interests in the appli- effects, predicts magnetic damping of cation of liquid metal to fusion devices surface waves, in good agreement with also add new demands for a better un- the experimental results. Two-dimension- derstanding of MHD physics of electri- al waves are made by shaking the liquid cally conducting fl uids. This experiment vertically (Faraday waves), and the MHD focuses on MHD effects on fl uid turbu- effects are investigated when a direct cur- lence and surface waves using liquid gal- rent magnetic fi eld is imposed horizontal- lium, which can be well approximated by ly. Figure 14 shows images taken during MHD models. Three basic physics issues a preliminary experiment, which indicate will be addressed. (1) When and how do possible effects on the pattern formation MHD effects modify surface stability, ei- due to the magnetic fi eld. ther in linear regimes or nonlinear re- Experiments on liquid gallium fl ow gimes such as solitary waves? (2) When across an imposed magnetic fi eld have and how do MHD effects modify a free- begun using a newly constructed gallium surface fl ow, such as by surface deforma- loop. Existence of a free surface distin- tion? (3) When and how do MHD ef- guishes this problem apart from the tradi- fects modify thermal convection? tional Hartman fl ow, which has been in- In neutral fl uids such as water, de- tensively studied. Stability of such fl ows pending on wavelength, gravity force bears important consequences to the fu- and surface tension force are dominant sion reactor application. Interfacial sta-

94 bility is also relevant to the mixing pro- nance with the gravity waves to efﬁ cient- cesses in many astrophysical phenomena. ly mix light and heavy materials. Collab- When a ﬂ owing layer of light material orations on this topic are under way with sits on top of a layer of heavy material, Professor R. Rosner of the University of the interface can be unstable due to reso- Chicago.

Figure 14. Images taken during a vertical shaking (25 Hz) of a liquid gallium alloy dish. Square patterns (left) form without magnetic fi eld. When a magnetic fi eld of about 1,300 G is imposed parallel to the liquid surface, the patterns are seen to align with the magnetic fi eld (right).

95 96 National Compact Stellarator Experiment

National Compact Stellarator Experiment

key goal for fusion energy re- and Germany’s Wendelstein-7X experi- search is to develop physics so- ments, large facilities that use supercon- A lutions for practical magnetic fu- ducting magnets. United States research- sion power plants. Stellarators, a family ers have focused on a new variant, the of three-dimensional toroidal magnet- compact stellarator, which shares the at- ic conﬁ gurations, are of interest because tractive properties of existing stellarators they solve the major problems — achiev- but also has additional advantage. ing steady-state operation and avoiding The compact stellarator concept is a re- plasma disruptions. There is a substantial sult of major advances in plasma physics effort in stellarator research worldwide, understanding and computation over the including Japan’s Large Helical Device past decade. For the ﬁ rst time, research-

97 ers are able to design stellarator confi g- estimates in detail. Three in-depth proj- urations that are stable without active ect reviews were conducted to assess the feedback control or current drive, have project’s progress as documented in the low aspect ratio (A ≤ 4.5, where A is the Preliminary Design Report. They unani- ratio of the torus radius to plasma radi- mously concluded that NCSX was ready us) compared to previous stellarator de- to be baselined in the U.S. Department signs (A ≤ 10), and have a quasi-symmet- of Energy (DOE) system, and recom- ric magnetic fi eld structure. mended DOE approval of Critical Deci- A quasi-symmetric magnetic confi gura- sion 2 (CD-2), Approval of the Project tion has, in spite of its three-dimension- Baseline. al geometry, an approximate symmetry direction in the fi eld strength, as experienced NCSX Mission by charged particles drifting along mag- The NCSX is an integral part of the netic fi eld lines in the system. In a quasi- DOE’s Offi ce of Fusion Energy Sciences axisymmetric stellarator, such as the Na- program, its mission being to acquire the tional Compact Stellarator Experiment, physics knowledge needed to evaluate the single particle trajectories and plasma compact stellarators as a fusion concept fl ow damping are similar to those in toka- and to advance the physics understand- maks, which are axisymmetric in both ge- ing of three-dimensional plasmas for fu- ometry and magnetic structure. Based on sion and basic science. In addition, the this fundamental similarity, quasi-axisym- technological innovations and develop- metric stellarators are expected to share ments that are produced in the course of the tokamak’s good confi nement perfor- the fabrication project are making impor- mance. Their physics link with tokamaks tant contributions to fusion technology, should enable compact stellarators to ad- including publications in major confer- vance rapidly and economically, building ence proceedings. The device (shown on on advances in the more mature tokamak page 95) is designed to test compact stel- concept, including the expected advances larator physics in a high-beta (β > 4%), in burning plasma physics and technolo- low aspect ratio (A ≤ 4.4) quasi-axisym- gy from ITER. metric stellarator (QAS) plasma confi g- A new experimental device, the Na- uration, which obtains about one-fourth tional Compact Stellarator Experiment of its edge rotational transform from the (NCSX), is being constructed at the self-generated bootstrap current. Modu- Princeton Plasma Physics Laboratory lar coils (Figure 1) provide the externally (PPPL) in partnership with the Oak generated three-dimensional stellarator Ridge National Laboratory as the center- magnetic fi elds for the three-period con- piece of a national program to develop fi guration. The QAS concept was chosen compact stellarators. During FY03, the for NCSX because its connection with NCSX fabrication project offi cially start- the tokamak enables it to build on the ed. Good progress on its design permitted tokamak database as well as the stellara- the project to advance from the concep- tor database. tual design level to a level of maturity suffi cient to establish the cost and schedule NCSX Technical Advances baseline for project execution. A Prelimi- The NCSX design is built upon the nary Design Report was prepared, docu- robust machine concept that was docu- menting the project’s designs, plans, and mented in the 2002 Conceptual Design

98 Figure 1. The NCSX uses three-dimensional modular coils to produce a three-dimensional plasma shape.

Report. At the core of the device are the During FY03, the project completed modular coils and the vacuum vessel, the its advanced conceptual design and pre- two most critical components. The eigh- liminary (Title I) design phases. Subcon- teen modular coils will be fabricated at tracts for manufacturing development of PPPL on steel winding forms manufac- the modular coil winding forms and vac- tured in industry to precise shape spec- uum vessel were awarded to four indus- ifi cations. The fi nished coils will be as- trial teams. They proceeded to develop sembled over segments of the vacuum detailed plans and cost and schedule es- vessel, also manufactured in industry, timates for fabricating these highly de- to form three identical fi eld-period sub- velopmental components. An in-house assemblies. These components and as- program was initiated to develop the pro- sembly steps are illustrated schematically cesses for fabricating the modular coils in Figure 2. In fi nal assembly, the fi eld- on the winding forms, to develop the period subassemblies will be joined to- metrology methods required to measure gether on a support base to form a vacu- these complex shapes, and to quantify the um-tight vessel surrounded by a toroidal composite material properties of the con- shell structure, made up of the eighteen ductor pack. Details of the technical ad- winding forms, that supports the modu- vances made in FY03 are described in the lar coils. Additional control coils, associ- Engineering and Technical Infrastructure ated structures and services, and a cryo- section of this Annual Highlights Report. stat will then be installed to complete the In summary, in FY03 the technical ba- stellarator core assembly. sis for NCSX advanced considerably in

99 Figure 2. Manufacture and assembly of the NCSX modular coils and vacuum vessel into fi eld-period subassemblies. its degree of detail and self-consistency. Mitigating the Risk The cost and schedule estimates for all of Major Operational Outages work packages were updated, based on Access to critical NCSX components, these advances, to support the baselining for example the modular coils, will be dif- of the project. fi cult in the assembled device. Recovery from a coil failure would likely involve Risk Management a costly and lengthy engineering effort Risk is an element of any project, but to remove a large amount of equipment especially so in the fabrication of a unique and would severely impact the ongoing science research facility such as NCSX. research program. The risk of a mechan- The identifi cation and evaluation of proj- ical coil failure is mitigated by engineer- ect risks and their consequences and the ing analysis, conservative design criteria, incorporation of risk mitigation measures and an active coil protection system. Inde- in the project baseline are key parts of the pendent groups using different codes and project planning process. Both DOE and models perform critical analyses, such as PPPL are increasingly emphasizing risk electromagnetic load, stress, and defl ec- mitigation in their project management tion calculations and thermal stress cal- approaches. culations. The stresses are compared to al- The NCSX risk management ap- lowable values documented in the NCSX proach, critical risks, and mitigation Structural Design Criteria. The materi- plans were documented to support the als chosen for the coil winding form have project baselining. Here is described been demonstrated to have extremely high some of the project-level risk mitigation tensile strength, which provides addition- measures that have been included in the al margin. Conductor pack properties are NCSX project plans. determined through testing.

100 The risk of electrical failure is addressed to assess implications of design tradeoffs via careful control of the coil winding on physics performance. Adequate bud- process. It will be performed and over- gets for these activities, which are impor- seen by Laboratory staff experienced in tant for minimizing downstream surpris- fusion magnet fabrication and operation. es and controlling risks, are included in The process will be developed and the project plans. staff will be qualifi ed through the wind- Competition for major production ing development program. Ample quali- contracts is maintained by qualifying two ty assurance and control will be provid- suppliers each for the modular coil wind- ed. Lessons learned from previous fusion ing forms and vacuum vessel. Each sup- magnet-related failures have been ap- plier is developing its own processes for plied. For example, the project has added manufacturing the components and will resources and organizational visibility in demonstrate those processes by fabricat- the area of technical assurance to provide ing full-scale prototypes. The production extra attention to the analysis and testing suppliers will be selected based on their activities that will be performed to verify overall performance, evaluation of their the adequacy of the coil design. prototypes, and their production proposals. Mitigating the Risk Finally, adequate budget and sched- of Cost and Schedule Overruns ule contingencies, both important ele- Failure to execute the NCSX project ments of risk mitigation, are included within the planned schedule and fund- in the baseline. The budget contingen- ing envelope could delay or limit the sci- cy is 26% of remaining work scope at entifi c output from NCSX and impact the time of baselining, supported by the other parts of the fusion program that work package managers’ analyses of risks are depending on it. The primary means at the component and subsystem level. A of minimizing NCSX cost and schedule schedule contingency of fi ve and one-half risks is to base the estimates on a mature months is included to mitigate the risk design that is amply supported by anal- of schedule delays along the critical path. ysis and manufacturing development. In Incentive contracts for component man- keeping with current DOE project manufacture and the use of two winding lines agement practices, the NCSX baseline are also available as measures to mitigate has been established at the preliminary schedule risks. design stage so that the costs and risks to meet project requirements are well un- Value Engineering derstood. Industrial manufacturers have In preparation for establishing the provided estimates for the highest-risk baseline, a value engineering study of the components based on detailed processing design was conducted using a task force plans, which they have developed. composed of both members and non- The NCSX project management has members of the NCSX team. The task implemented a system engineering pro- force was charged to identify possible gram to provide timely identifi cation and changes in the NCSX project plans that analysis of requirements, system-level as- could reduce estimated costs without sig- sessments of design choices, design in- nifi cantly impacting or delaying perfor- tegration, and control of interfaces. A mance. They analyzed and reviewed ma- physics analysis activity is maintained jor systems in the NCSX project for the

101 purpose of achieving the required func- changes reduced risk or increased confi - tions at the lowest cost. dence in achieving project design goals. The value engineering team conducted a series of brainstorming meetings Cost and Schedule Baseline with work package managers and proj- As the fi nal step in preparing the Pre- ect management. During each meeting, liminary Design Report, an updated cost the scope, design, and estimated cost of and schedule estimate for completing the lower-level work elements were reviewed NCSX project was developed. The es- and discussed. Alternative methods for timates and associated contingency re- achieving the necessary functionality quirements were developed by the work were proposed and explored. Many of package managers based on well-estab- the ideas discussed were quickly shown to lished technical requirements for each not be advantageous and were discarded. system. The estimating basis includes de- Changes that appeared viable and prom- tailed design data, a detailed work break- ising were identifi ed for further investi- down, a manufacturing analyses for the gation and analysis. Follow up meetings critical stellarator core systems, test re- were held to discuss the results of the in- sults showing that legacy equipment to vestigations, modify and iterate the probe used on the project is in good condi- posed changes, and clarify whether they tion, and actual cost and schedule data were advantageous or not. Examples of for equipment items that are new but changes evaluated in the value engineer- based on proven designs. The estimate ing study are briefl y summarized below. included costs of activities planned to mitigate identifi ed risks, such as manu- • Local Control of Equipment. Since facturing development, system engineer- the NCSX control room will be ad- ing, and a construction work control cen- jacent to the NCSX torus hall, con- ter. The project budget of $86.3 million trol systems can make greater use at the time of CD-2, including contin- of local control than was originally gency of 26% on the work remaining, is planned. The change to local con- summarized in Table 1. trols was accepted, since they are The schedule critical path runs pri- easier and less costly to implement marily through the design and fabrica- than remote controls, resulting in a tion of the modular coils, fi eld-period $1.5-million savings. and machine assembly, and integrated • Simplifi ed Residual Gas Analyz- system testing. Vacuum vessel fabrication er and Gas Handling. Simplifi ed re- is close to the critical path. Project com- sidual gas analyzer and gas handling pletion is scheduled for May 2008, in- systems were proposed, making use cluding an overall schedule contingency of the local access and control op- of fi ve and one-half months to mitigate portunities afforded by NCSX. This schedule risks. The summary schedule is change was accepted, resulting in a shown in Figure 3. $130-thousand cost savings. Summary and Project Status In all, the task force documented sav- The progress made in NCSX design ings of approximately $3.4 million from and manufacturing development in changes that were proposed and accept- FY03 established a high degree of de- ed. In addition, several of the accepted sign maturity and self-consistency in the

102 Table 1. The National Compact Stellarator Experiment Project Budget.

WBS Work Package Budget ($M) 1 Stellarator Core 42.3 2 Heating, Fueling, and Vacuum 1.6 3 Diagnostics 1.7 4 Electrical Power 5.3 5 Central I&C and Data Acquisition 2.6 6 Facility Systems 2.0 7 Test Cell Preparation and Machine Assembly 4.3 8 Project Management and Integration 10.6 Subtotal 70.4 Contingency (26% of work remaining at CD-2) 15.9 Total Estimated Cost 86.3

Figure 3. The National Compact Stellarator Experiment Project Schedule.

NCSX technical basis. Special attention timates were updated at the end of ﬁ scal was given to identifying project risks, in- year 2003 in preparation for a series of cluding measures to mitigate those risks project reviews. Following the reviews, in the project estimates. The value engi- which unanimously concluded that the neering methodology was used to reex- project was ready to be baselined, the amine the system design and assure that U.S. Department of Energy established it provided the required functions at the a baseline budget of $86.3 million with lowest cost. Signiﬁ cant cost savings were project completion scheduled for May found. The project cost and schedule es- 2008.

103 104 Fusion Ignition Research Experiment

Fusion Ignition Research Experiment

he National Research Council ing plasma experiment to the U.S. (NRC) under the auspices of the fusion science program is clear. T National Academies formed a There is now high confi dence in Burning Plasma Assessment Committee the readiness to proceed to the (BPAC) in 2002 that found: burning plasma step because of the progress made in fusion science “A burning plasma experiment is and technology. Progress toward critically needed to advance fu- the fusion energy goal requires this sion science,” and recommended step, and the tokamak is the only that: “The United States should fusion confi guration ready for im- participate in a burning plasma ex- plementing such an experiment.” periment. Participation in a burning plasma experiment is a critical In accordance with the NRC-BPAC missing element in the U.S. fusion and the Fusion Energy Sciences Advisory program. The scientifi c and tech- Committee (FESAC) recommendations, nological case for adding a burn- the U.S. has joined international nego-

105 tiations to determine the site, cost shar- opment of an attractive tokamak power ing, and management structure of ITER plant. The basic parameters of FIRE were (“The Way” Latin). In addition, precon- chosen to make it a 40% scale model test ceptual design work on the Fusion Igni- of the ARIES-Reversed Shear (ARIES- tion Research Experiment (FIRE), a back- RS) physics design (Table 1). The pro- up burning plasma experiment, is being jected FIRE plasma parameters are close carried out in the U.S. as recommended to those of ARIES-RS and would provide by the FESAC, and in accordance with a valuable facility for exploring the phys- recommendations of the NRC-BPAC ics of reactor-like burning plasmas. to “develop other options for a burning Since Snowmass, signifi cant progress plasma experiment in case ITER con- has been made in improving the phys- struction is not approved by the negoti- ics basis for FIRE. Results from ongo- ating parties.” ing tokamak experiments continue to The goal of the FIRE preconceptu- indicate that strong plasma shaping, as al design study is to defi ne a low-cost present in FIRE, promotes increased H- burning plasma experiment to attain, ex- mode confi nement, enhances beta lim- plore, understand, and optimize magnet- its, and reduces the deleterious edge-lo- ically confi ned fusion-dominated plas- calized mode (ELM) to a more benign mas. The key technical objectives for form. FIRE are to address the critical burning The area of greatest progress on FIRE plasma issues of an attractive magnet- has been the development of a “steady- ic fusion power plant as envisioned by state” high-beta advanced tokamak con- the Advanced Reactor Innovation Eval- fi guration. This confi guration in FIRE uation Studies (ARIES). The FIRE De- relies on ion-cyclotron range-of-frequen- sign study has been undertaken as a na- cies (ICRF) fast-wave (FW) on-axis cur- tional collaboration with more than 50 rent drive and lower-hybrid (LH) off-axis participants from more than 15 U.S. in- current drive. With the existing two-strap stitutions, and is managed through the antenna design, the on-axis ICRF/FW Virtual Laboratory for Technology. The system can provide 200 kA of current by technical work on FIRE has been guided injecting 20 MW of power. Typical ad- by a Next-step Option Program Advisory vanced tokamak plasmas require less than Committee (NSO-PAC), with members 200 kA. Upgrades to four-strap antennas from 12 U.S. fusion institutions and Eu- would improve the current-drive effi cien- rope and Japan. cy. Off-axis current drive in FIRE is critical for establishing and controlling the Burning Plasma Physics Relevant safety factor profi le and is accomplished to an Advanced Fusion Reactor using up to 30 MW of lower-hybrid cur- The Advanced Reactor Innovation rent drive (LHCD) at 5 GHz. The expe- Evaluation Studies (ARIES) have shown rience developed on the planned Alcator that an economically attractive tokamak C-Mod advanced tokamak experiment power plant will require more than 80% (at the Massachusetts Institute of Tech- plasma self-heating, with more than 90% nology) with LHCD will strengthen the of the confi ning magnetic fi eld self-gen- basis for FIRE projections. erated. The overall theme of FIRE is to Bootstrap-consistent equilibrium and test the advanced tokamak features iden- stability analyses show that the high to- tifi ed by ARIES as essential to the devel- roidal mode number n ballooning lim-

106 Table 1. Comparison of FIRE Advanced Tokamak Parameters with ARIES-RS Parameters.

Parameters FIRE ARIES-RS

Plasma Elongation (κx) 2.0 2.0

Plasma Triangularity (δx) 0.7 0.7 Plasma Aspect Ratio (R/a) 3.6 4.0 Divertor Conﬁ guration Double Null Double Null

Normalized Beta (βN), AT Mode ~4 4.8

Bootstrap Fraction (fbs), AT Mode ~80% 88% Noninductive Current Drive 100% 100% Plasma Current Proﬁ le Equilibration 86 to 99% 100%

Toroidal Magnetic Field (BT) 6.5 to 10 T 8 T Major Radius (R) 2.14 m 5.5 m Minor Radius (a) 0.59 m 1.38 m Plasma Volume 27 m2 350 m2 Fusion Power Density 5.6 MW/m3 6.2 MW/m3 Neutron Wall Loading 2.7 MW/m2 4 MW/m2 Divertor Target Material Tungsten Tungsten

it for typical plasmas consistent with ex- the n = 1 resistive wall mode up to 80- ternal current drive is beta normalized 90% of the “with wall” limit. The anal- βN > 4.7. With no wall, the ideal-MHD ysis of the resistive wall mode stabiliza- beta-normalized limits for n = 1, 2, and tion is benefi ting from the experimental 3 are 2.7, 3.6, and 4.0, respectively. With progress on the DIII-D tokamak at Gen- a wall located at b/a = 1.35 on the out- eral Atomics in California. The plasma board side only, the ideal-MHD beta- confi gurations targeted have safety fac- normalized limits for n = 1, 2, and 3 are tor values above 2.0 everywhere, so that 6.1, 5.3, and 5.1, respectively. the m/n = 5/2 and 3/1 are the lowest-or- In FIRE, there are 16 large (0.75-m by der neoclassical tearing modes of interest. 1.5-m) ports at the outboard midplane Stabilization of the neoclassical tearing that are then fi lled by a fi rst-wall neu- modes using electron cyclotron current tron-shield assembly that can also con- drive from the low-fi eld side at a toroi- tain a resistive wall mode (RWM) coil, dal fi eld of 6.5 T would require frequen- radio-frequency launcher, and diagnos- cies of 140-170 GHz, which is close to tics. Calculations show that feedback the range of achieved values in the high- coils, located near the front face of the power long-pulse gyrotron research and fi rst-wall neutron-shield assembly in ev- development program. The LHCD sys- ery other midplane port, could stabilize tem could also be used by launching two

107 spectra, one for bulk current drive and Viable solutions must be within the the other for neoclassical tearing mode engineering limits set by the heating of suppression. the cryogenically cooled toroidal-fi eld coils, stresses due to nuclear heating of H-Mode Operating Space the vacuum vessel, a temperature lim- A wide range of H-mode plasmas have it of 600 °C for the fi rst-wall beryllium been examined using a global systems tiles, particle power to the outboard di- analysis code. The major radius (R), mi- vertor (<28 MW), and the radiated pow- nor radius (a), elongation (κ), triangular- er load on the divertor and baffl e (<6-8 ity (δ), and aspect ratio (A) are fi xed at MWm-2). Increasing the radiated power the reference edge-localized H-mode inin the divertor reduced the particle heat ductively driven design point: load and expanded the operating space signifi cantly. R = 2.14 m, For most H-mode plasmas at 10 T, a = 0.595 m, the toroidal-fi eld coil limited the plasma duration to 20 s, which is 2τ (the cur- κx = 2.0, CR δ = 0.7, and rent redistribution time) for the refer- x ence operating point and is the same as A = 3.6. the reference ITER H-mode duration. The analysis used for operating point The nominal operating point, shown as calculations incorporated plasma pow- the circle at 150 MW with a 20-s fl at- er and particle balance, in addition to top in Figure 1, has signifi cant mar- several other global parameter relations. gin to handle increased fusion power. If In particular, ITER98(y,2) scaling is as- plasmas up to the no-wall stability limit sumed for the global energy confi nement of βN ≈ 3 can be attained, fusion power time. The plasmas considered spanned levels of 350 MW could be sustained for the ranges: 10 s. High-Q (15 to 30) operation could be attained for cases with low impurity 5 ≤ Q ≤ 30, content (1-2% beryllium), modest density peaking n(0)/〈n〉 = 1.25, Greenwald 5 ≤ Paux (MW) ≤ 30, density n/n = 0.7 to 1.0, and H-mode 1.05 ≤ n(0)/〈n〉 ≤ 1.25, Gr scaling multiplier H98(y,2) = 1.03 to 0.3 ≤ n/nGr ≤ 1, and 1.1. 1.5 ≤ βN ≤ 3, AT Mode Operating Space where Q is the ratio of the fusion pow- A similar global analysis has been used er produced to the power used to heat to determine the operating space for a plasma, P is auxiliary heating pow- aux 100% noninductive advanced tokamak er, n(0)/〈n〉 is the density profi le peak- modes in FIRE. An expression for the ing, n/n is the Greenwald density, and Gr bootstrap current fraction is included, β is beta normalized. In addition, the N and the current drive power is given by: impurity concentrations in the plasma core were varied over 1 to 3% for be- PCD = [nRIp(1-fbs)]/ηCD, ryllium and 0.0 to 0.3% for argon, allowing higher radiated power fractions where n is density, R is major radius, Ip is to more optimally distribute the exhaust plasma current, fbs is bootstrap current, power. and ηCD is current drive effi ciency.

108 B T = 10 T, IP = 7.7 MA 400 TF Coil Limit FW Be Temp Limit 600 °C 300 VV Neutron Heating Limit

200 Fusion Power, MW Fusion Power,

100 βN ≤ 3.0% ≤ 2.0 Prad (div) ≤ 60% ≤ 1.75 P ≤ 30 ≤ SOL 1.5 ≤ 10 0 0 10 20 30 Flattop Time (s) Figure 1. Operating space for conventional inductively driven high- conﬁ nement modes in FIRE.

The on-axis current drive is fi xed at centrations are varied between 1 to 3% 200 kA from ICRF/FW, so that LHCD for beryllium and 0.0 to 0.3% for argon, must make up any current not driven by allowing higher radiated power fractions. the bootstrap effect. The current-drive The operating space can be expanded by effi ciency used in these scans is ηCD = increasing argon in the plasma to radiate 0.2 and 0.16 A/Wm2 for ICRF/FW and more power in the divertor and on the LH, respectively, and is based on detailed fi rst wall resulting in 1.5 ≤ Zeff ≤ 2.3. The LH and ICRF/FW analysis for FIRE. fraction of power radiated in the divertor The operating space was scanned for cas- to power exhausted into the scrape-off es with Q = 5, at: layer was allowed to vary to 10%, 30% and 60%. The same power-handling lim- BT = 6.5 T, its were imposed as for the H-mode de- PLH ≤ 30 MW, scribed above. The nominal operating point has 150 MW of fusion power for PICRF ≤ 30 MW, 32-s fl attop. The fl attop burn times for 1.05 ≤ n(0)/〈n〉 ≤ 2, these advanced tokamak plasmas are lim- 2 ≤ T(0)/〈T〉 ≤ 3, ited primarily by the nuclear heating in 0.3 ≤ n/nGr ≤ 1, the vacuum vessel rather than toroidal- 3.25 ≤ q95 ≤ 5, and fi eld coil heating. 3 ≤ β ≤ 4.5. Imposing these constraints, the system N study found that FIRE could attain high- where BT is the toroidal magnetic fi eld, beta high-bootstrap advanced tokamak PLH is lower-hybrid heating power, PICRF plasmas with near steady-state conditions is ICRF heating power, and q95 is the for up to 5τCR, as shown in Figure 2. If edge safety factor. the vacuum vessel/shield was modifi ed to Attainment of βN ≈ 3 will require withstand the nuclear heating induced feedback stabilization of the resistive wall stresses, the reference advanced tokamak modes. In addition, the impurity con- pulse length could be extended to ≈50 s

109 B T = 6.5 T, I P = 4.5 MA 400 PF Coil limit

Div Cond for full l i and β Pwr Limit p range 300 FW Be Temp Limit 600 °C TF Coil Limit VV Nuc. Heat Limit 200 Fusion Power, MW Fusion Power,

100 βN ≤ 4.5% ≤ 4.0 Prad (div) ≤ 60% ≤ 3.5 P ≤ 30 ≤ SOL 3.0 ≤ 10 0 01020 30 40 50 60 Flattop Time (s) Figure 2. Operating space for “steady-state” (100% noninductive) high-beta advanced tokamak modes in FIRE.

(5-6τCR). These Q = 5 plasmas require during the fl attop burn phase. A simula- confi nement corresponding to H98(y,2) tion of the plasma response to a perturba- ranging from 1.4 to 1.8 similar to those tion (Figure 3) produced by a drop in the required in ITER. At the higher ranges lower-hybrid current drive shows that the of confi nement, H98(y,2) = 1.6 to 2.0, plasma duration is suffi cient to study the Q = 10 plasmas are produced that have a evolution of a fusion dominated plasma reduced duration of 1-3τCR. on the current evolution time scale.

Computer Simulation FIRE Engineering Activities of Burning Plasma Phenomena The FIRE engineering design was re- The rapid growth in computing power viewed in detail at Snowmass, and the as- is enabling more realistic simulations of sessment team found that there were no complex plasma phenomena. The Scien- feasibility issues with respect to the con- tifi c Discovery through Advanced Com- struction of FIRE. It was noted that the puting Program (SciDAC) simulations of FIRE magnet design has the least com- steady-state high-beta advanced tokamak plex magnet structure of the three pro- plasma discharges with 100% noninduc- posed burning plasma experiments, and tive current composed of fast-wave, low- increased complexity often leads to de- er-hybrid, and bootstrap currents that are creased reliability. FIRE researchers have sustained for more than 3τCR have been provided a detailed project cost esti- done for FIRE using the Tokamak Simu- mate based upon industrial vendor and lation Code. This is accomplished by pro- in-house quotes. The FIRE total proj- gramming the heating and current-drive ect cost estimate of $1.186 B (FY 2002), sources so that the inductive contribution including 25% contingency, was found to the plasma current is reduced to zero to be reasonable by the Snowmass As- by the end of the ramp up, so the safe- sessment team. The cost estimate of the ty factor profi le has no signifi cant change tokamak assembly (everything inside the

110 40 Alpha Power

30 LH + ICRF

20 Lower Hybrid Power 10 Power (MW) 0 H, He Radiation Be, Ar Radiation -10

Total 4 Non-inductive

3 Bootstrap 2

Current (MA) 1 Fast Wave Lower Hybrid 0 0 10 20 30 40 Time (s) Figure 3. Simulation of the evolution of a current pulse perturbation in a “steady-state,” high-beta, advanced tokamak mode in a FIRE plasma discharge. cryogenic Dewar) is $280 M without be accessed within the engineering lim- contingency. itations of the device. Improved disrup- There were a number of technical is- tion calculations and minor modifi ca- sues identifi ed at the Snowmass meeting tions to divertor/vacuum vessel support that will require additional work includ- show that the FIRE design is suffi cient to ing: power handling during edge-localized withstand plasma disruptions. modes and plasma disruptions, verifi cation of lower-hybrid capability for neo- FIRE Outreach Program classical tearing mode stabilization, in- The FIRE project continued its proac- creased advanced tokamak capability and tive outreach program with 14 presenta- pulse length, and pulse repetition rate. tions at fusion institutions and meetings, FIRE scientists have modifi ed the de- active participation in the Internation- sign of the toroidal-fi eld coils to include a al Tokamak Physics Activity, the 2002 second cooling tube that would increase American Physical Society Division of the repetition rate to once per hour at full Plasma Physics Meeting, the 2003 Amer- fi eld and pulse length. Several approach- ican Physical Society Spring Meeting, the es are being investigated to increase the 18th Symposium on Fusion Engineer- number of pulses (total fusion energy ing, the 30th European Physical Society yield) including a Small Business Innova- Conference on Plasma Physics and Con- tive Research Program (SBIR) to develop trolled Fusion, and the 19th Internation- improved inorganic magnet insulation al Atomic Energy Agency Fusion Energy that would be compatible with fusion re- Conference. In addition, the FIRE web- actor requirements. The operating space site was maintained as a site of FIRE doc- for advanced tokamak plasmas has been umentation and information for the fu- established showing that up to 5τCR can sion program.

111 112 Engineering and Technical Infrastructure

he Princeton Plasma Physics availability — the highest attained at the Laboratory (PPPL) Engineering beginning of any NSTX operating peri- T and Technical Infrastructure De- od. During the fi rst four weeks, NSTX partment is responsible for managing the had 603 plasma attempts and took data Laboratory’s engineering resources. This on 515 plasmas. At the end of the fourth includes a staff of engineers, technicians, week, however, a bolted joint in the to- and support staff organized functional- roidal-fi eld (TF) circuit failed, ending the ly (Mechanical; Electrical; Computer; experimental run for FY03. Recovery re- and Fabrication, Operations, and Main- quired a redesign of the TF hub and joint tenance Divisions) to support the Labo- assembly and the manufacture of a new ratory’s research endeavors. The Depart- TF center conductor (see below). ment is responsible for the technological During the break-in operations for infrastructure of the Laboratory’s exper- the design and fabrication of the new TF iments as well as the “caretaking” of the center conductor, time was taken to make C- and D-site experimental facilities. improvements to various NSTX subsystems. A reconfi guration of the ohm- NSTX Engineering ic-heating (OH) rectifi ers was complet- Engineering Operations ed that allows for a more symmetric OH Prior to the start of the Nation- power supply confi guration and makes al Spherical Torus Experiment (NSTX) available an additional power supply for FY03 experimental run, maintenance the future resistive wall mode coils. This and upgrades to improve the operation- reconfi guration will also provide the op- al reliability of technical subsystems were tion for bipolar operation of poloidal- completed. Extensive maintenance of the fi eld (PF) coil set fi ve (PF5), as well as fi eld coil power conversion rectifi ers was the powering of the PF4 coil set. A new performed and the current feedback de- inner wall gas injection system was devices (Halmars) were reconfi gured to signed and installed, and engineering re- provide consistent signal defi nition for views were completed for performing different operating modes. High-speed vacuum vessel boronization during bake- voltage transient monitoring and over- out. Hardware and software upgrades voltage protection systems were installed were completed that will reduce the plas- on the vacuum vessel segments in prepa- ma control system latency, ultimately en- ration for upcoming coaxial helicity in- abling higher plasma elongation. jection experiments. The FY03 NSTX experimental run pe- Toroidal-fi eld Redesign riod started on schedule and during the One of the key features, but also one early weeks operated at more than 90% of the most challenging engineering as-

113 bly was not adequate, and repeated application of the electromagnetic loads led to unanticipated loads in the bolts and high local current density, which eventually led to failure of the assembly. Due to extensive damage, it was not possible to recover the original TF inner leg assembly. Furthermore, it was clear that an improved design was needed. Therefore a recovery effort was initiated, beginning with the development of a new TF inner leg assembly design. Figure 1. Cutaway view of the National The new design (Figure 3) incorpo- Spherical Torus Experiment showing the rates features which address all of the demountable toroidal-ﬁ eld coil and ﬂ ag shortcomings of the original design, in- joint. cluding the following:

pects, of the spherical torus (ST) is the • hub assembly stiffness is dramatical- demountable toroidal-fi eld assembly. As ly increased, depicted in Figure 1, the so-called fl ag • fl ags are contained in steel boxes joint provides a removable connection with injected epoxy fi lling the space between the inner and outer leg assem- between, blies, which permits removal of the entire inner leg and center stack assembly • fl ag fasteners are larger diameter for maintenance. and tightened to twice the force of On February 14, 2003, following the the original design, morning test shots, the NSTX toroi- • shear keys are added to resist the dal-fi eld inner leg assembly failed at the vertical electromagnetic force, and lower inner leg-to-fl ag joint. Analysis of the event identifi ed shortcomings in the structural design of the joint, which led to failure after some 7,200 machine pulses, with a limited number at the full magnetic-fi eld rating of 6 kG. As depicted in Figure 2, the stiffness of the hub assem-

Unanticipated Deflection Bolt Loads of Hub (typical) EM Assembly Load Hub Assembly TF Bundle

High Preload Current (bolts) Density Hub Assembly Figure 2. Drawing of how the repeated application of electromagnetic loads led to structural failure of the lower TF ﬂ ag joint. Figure 3. CAD model of the TF ﬂ ag joint.

114 • voltage probes are provided in-situ instrumentation which includes a new to measure the resistance of every fi ber-optic strain, temperature, and dis- joint. placement monitoring system, reliable operation at full-rated parameters is ful- Extensive engineering resources were ly anticipated. Although the failure was applied to the redesign effort to ensure a unfortunate, it has led to an improved successful outcome while minimizing re- understanding of the TF joint behavior, covery time. An extensive fi nite element which is directly applicable to the design analysis was performed to develop an un- of next-step ST devices. derstanding of the structural and thermal behavior of the joint and to guide the de- Toroidal-fi eld New Center velopment of the new design. Teams of Bundle Manufacture magnet experts from other fusion labs The new toroidal-fi eld inner bun- conducted two technical reviews. Tests dle and support structure (Hub) was de- were performed to characterize the elec- signed and fabricated at the PPPL facili- trical resistivity of the joint versus pres- ty. The bundle is constructed of thirty-six sure, the friction coeffi cient of the joint, insulated copper conductors, which are the pull-out strength of the fasteners, and water-cooled via a copper tube soldered other features. In addition, a mechani- along the conductor length. Each conduc- cal prototype was exercised at the rated tor was sandblasted, primed and hand in- number of cycles of full mechanical loads sulated using a B-stage epoxy impregnat- at elevated temperature, and an electrical ed tape. The conductors were then press prototype was tested at full current for molded at curing temperature into their the full-time duration at full mechanical fi nal confi guration using a press mold in loads. a new oven that was designed and fab- Based on the new design, the success- ricated at PPPL for this operation (Fig- ful prototype testing, and the improved ure 4).

Figure 4. The new oven designed and built at PPPL for the press molding and curing of NSTX’s redesigned TF inner bundle.

115 Figure 5. Cutaway view showing the major components of the National Compact Stellara- tor Experiment.

NCSX Engineering sembly to assure accurate fi t-up. This seg- During FY03, tremendous progress mentation allows for installation of the was made on the engineering design of modular coils. the National Compact Stellarator Experi- The modular coil system, shown in ment (NCSX) in preparation for the Pre- Figure 7, consists of 18 coils (six each liminary Design Review scheduled for of three coil types) wound directly onto the fi rst week of FY04. A successful Pre- liminary Design Review will allow the fi - nal design to proceed on schedule. Figure 5 is a cutaway view showing the key components of the NCSX. Ro- bust engineering designs were developed for all major systems of NCSX’s core, including the vacuum vessel, modular coils, TF coils, and PF coils. NCSX’s highly shaped vacuum vessel, shown in Figure 6, will be fabricated of press-formed 0.375-inch Inconel-625 panels welded together. The vessel will consist of three identical 120-degree seg- Figure 6. National Compact Stellarator Ex- ments that will be joined by welding via periment vacuum vessel assembly with ther- “spool pieces” machined just prior to as- mal insulation.

116 estimates, vendor estimates, and projections from similar PPPL experimental devices. The estimated cost of NCSX is $86 million including a 26% contingency. Although much of NCSX is conventional design and construction, two of NCSX’s key components, the vacuum vessel and modular coils, are unusual and challenging due primarily to their geo- Figure 7. National Compact Stellarator Ex- metric complexity. Consequently, par- periment modular coil assembly. ticular emphasis is placed on these two components to mitigate technical, sched- cast and machined stainless steel wind- ule, and fi nancial risks. Limited industrial ing forms. Coil system designs were very studies of the vacuum vessel and modular carefully optimized for physics perfor- coils were performed during the concep- mance while being consistent with en- tual design phase. This year, two indus- gineering constraints, such as stress and trial supplier teams in both of these areas temperature rise, and access requirements were awarded contracts for detailed man- for neutral-beam injection and diagnos- ufacturing studies that will culminate in tics. The coils are wound of compacted prototypes in mid-FY04 and proposals stranded cable which is vacuum pressure for the “production” manufacturing ef- impregnated with epoxy directly on the forts. The vessel prototype consists of a forms to form a strong monolithic struc- 20-degree segment with a vacuum port ture capable of reacting electromagnetic assembly. The winding-form prototype is loads as high as 7,000 pounds per inch. a full-scale, full-featured winding form of The winding forms are joined together by the most complex of the three winding bolting, resulting in a very rigid, continu- forms. The modular coils will be wound ous shell structure. The coils are conduc- at PPPL. Consequently, signifi cant R&D tion cooled by liquid-nitrogen chill plates efforts were undertaken focusing on key located on both sides of the windings. issues: vacuum-pressure impregnation, The TF system consists of 18 identi- winding methods required to meet the cal, wedged, copper windings support- NCSX’s stringent dimensional accuracy, ed by cast stainless steel structures that and development of winding details. are, in turn, supported by the modular coil shell. The TF generated by these coils supplements the TF component of NCSX Coil Winding R&D the modular coils to provide operation- There were a number of R&D and de- al fl exibility. Six pairs of copper PF coils sign activities in support of the NCSX surround the TF coils. They provide in- project during FY03. These centered ductive current drive as well as physics around the compacted copper rope con- fl exibility. ductor being used for the modular coils, Requirements, work scopes, and sched- as well as the associated epoxy system ules were developed for both the core and that will be used to impregnate those ancillary systems. Cost estimates were de- coils. Some of the R&D activities in- veloped using a combination of internal cluded conductor Keystone tests (Fig-

117 Figure 8. Conductor keystone test done on the NCSX modular coils. ure 8), which helped defi ne the conduc- were supplied by industry and delivered tor size, determine tolerance control and to PPPL shops where the fi nal fabrication develop manufacturing processes. Devel- and assembly will be completed. The au- opment of the epoxy-impregnation sys- toclave will be operational in March tem included the design of a “Bag Mold” 2004. The remaining tooling, such as to handle the complex geometry of the the turning fi xtures, conductor payout modular coils (Figure 9). In addition, test spools, winding clamps, etc. are in vari- specimens were fabricated to determine ous stages of design and fabrication. The the mechanical and thermal properties of complete winding facility will be opera- epoxy-impregnated conductors. tional by June 2004, in time for winding PPPL staff will fabricate the modular the fi rst prototype modular coil. coils in-house. The former Tokamak Fu- sion Test Reactor (TFTR) test cell will be utilized for winding the modular coils, as well as assembling the fi eld-period subassemblies. The design of the tooling and development of a manufacturing plan for modular coil fabrication was initiated this year. An autoclave, an oven chamber that can operate under vacuum or pressure environments, will be used during the epoxy impregnation of the modular coils. The main components of the au- Figure 9. The NCSX modular coil epoxy- toclave, such as the domes and chamber, impregnation system.

118 FIRE Engineering The engineering design of the Fusion Ignition Research Experiment (FIRE) with a 2.14-m major radius, adopted in FY02 in response to Snowmass Sum- mer Study recommendations, was updated during FY03. The updated design is shown in Figure 10. To enhance FIRE’s experimental pro- ductivity, cooling is now provided on both sides of the inner TF coil leg. This change permits a tripling of the pulse Figure 10. Updated design conﬁ guration of FIRE with a 2.14-m major radius. repetition rate from one pulse every three hours to one pulse every hour. A quasi- steady-state ARIES-like mode has been tended four-strap ion-cyclotron radio-

developed (normalized beta βN ~ 4; boot- frequency (ICRF) antenna with movable strap fraction f bs ~ 80%) for FIRE. The in-vacuum tuning is being evaluated. pulse length of the Advanced Tokamak This would be capable of providing 20 (AT) modes has been doubled up to MW of ICRF, operable over the range of

5τCR. The TF coil design is robust, with 70-120 MHz for heating and on-axis cur- the pulse length limitation being dictated rent drive. Resistive wall mode coils have primarily by nuclear heating of the vacu- been incorporated into the port plugs in um vessel and fi rst wall. The TF insula- the new design. A movable port plug de- tion radiation dose is 3 × 1010 rads. This sign is being evaluated for the baseline is within the expected limits of radiation- pumping confi guration. In-board pellet resistant insulation systems being devel- injection has been incorporated; this is oped in Small Business Innovative Re- an extremely high-leverage item for effi - search studies currently underway. The cient tritium use, density profi le peaking, PF design continues to evolve in parallel and burn control. with studies of a wide variety of AT oper- FIRE’s engineering improvements ating modes. Fatigue limits of the central have been driven by studies of a wide va- solenoid are the limiting factor for some riety of operating modes. The engineer- of the AT modes. Remote removal and ing report is currently being updated in replacement of the central solenoid at a preparation for a Physics Validation Re- safe fraction of its fatigue life is judged to view planned for FY04. be a possible (and practical) method of addressing this issue. Actively cooled in- NSST Engineering ner-divertor and baffl e modules and in- The rapid progress and scientifi c foun- dependently cooled outer-divertor mod- dation now being established by the ules will be utilized for improved thermal NSTX “Proof-of-Principle” experiment, performance. Remote-handling details along with the completion of Decontam- are currently being updated for the new ination and Decommissioning (D&D) of design. Plasma disruption load and stress TFTR, leads toward the possibility of con- calculations are currently underway for struction of a next-step “Performance Ex- the larger vessel, which has reduced wall tension” spherical torus (ST) experiment loading and improved cooling. An ex- at PPPL. Within the constraints of the fa-

119 cility, preliminary design point studies in- temperature rise, power, and energy con- dicate that a device with modest power sumption of the toroidal-fi eld, ohm- gain (Q ~ 2) and a pulse length of fi ve sec- ic-heating, and poloidal-fi eld magnets. onds can be realized. The level of plasma Using this tool an optimization was per- performance for the Next Step Spherical formed which aimed to maximize Q and Torus (NSST), Figure 11, would be of the minimize major radius within the con- same order as that required for a Compo- straint of the engineering allowables, in- nent Test Facility, thereby providing a key cluding the power (800 MW) and energy link to the fi rst practical application of fu- (4.5 GJ) available from the existing mo- sion technology. tor-generator system. Auxiliary heating The key issues for the ST are (1) char- power was limited to 30 MW, which is acterization of stability limits and con- available from existing equipment (P ≤ 32 fi nement, (2) power and particle han- MW, neutral-beam injection at 120 keV) dling, and (3) noninductive current and radio-frequency (P ≤ 10 MW at 30 start-up and sustainment. NSST would MHz). The primary target of the opti- aim to extend the knowledge base in mization was the fully inductive Q = 2 these areas beyond the levels achieved on scenario, but a long-pulse noninductive NSTX to a much larger scale, approach- scenario has also been identifi ed. At pres- ing burning plasma conditions with sig- ent, the design point stands at major ra- nifi cant alpha particle heating via a deu- dius R0 = 1.5 m, toroidal magnetic fi eld terium-tritium campaign toward the end BT = 2.6 T, aspect ratio A = 1.6, plasma of the NSST research program. current Ip = 10 MA, and fl attop time Tfl at To arrive at a design point for NSST, = 5 s. It may be appropriate to adjust the parametric studies were performed using design point as the NSTX progresses to- a systems code which includes an anal- ward higher performance regimes. ysis of the plasma along with engineer- Work has begun to develop engineering algorithms which calculate the stress, ing and physics concepts which satis-

Figure 11. The Next Step Spherical Torus (NSST) experiment.

120 fy the design point identifi ed by the sys- (7) Plasma-facing component heat tems code. The objectives are to confi rm loads and technologies; feasibility, identify physics issues, develop (8) Handling of center stack within a cost and schedule, and provide a link- the physical constraints of the ex- age to the NSTX research program (see isting test cell; Figure 12). The engineering studies have focused (9) Neutron fl ux, fl uence, and shield- on ten key issues: ing requirements; and (10) Overall power and energy match (1) TF inner leg torque reaction and to the PPPL site. shear stress in the inner-leg turn insulation; PBX-M Removal (2) TF inner-leg-to-outer-leg inter- During FY03, the removal of the Po- face, allowing for axial thermal loidal Beta Experiment-Modifi cation displacement of the inner legs, (PBX-M), formerly the Poloidal Di- and vertical separating force on vertor Experiment (PDX), was com- outer legs, without excessive ten- pleted safely, on-schedule, and within sion and compression; budget. The electrical safi ng and removal of components saved for reuse (3) TF joint and connector scheme; occurred between February 2002 and (4) TF outer-leg positioning, fi eld early June 2003. This included neutral- ripple, neutral-bean injection ac- beam heating systems, select fusion di- cess; agnostic systems, and PBX-M control room equipment. Following electrical (5) OH coil performance optimiza- safi ng, all items in the PBX-M and the tion; adjacent Princeton Large Torus control (6) TF and OH coil cooling; room and the lower-hybrid current-

Figure 12. Comparison of the NSST and the NSTX cross section.

121 drive power supply area were complete- entire vacuum vessel, was the largest at ly removed. 57,000 lbs (Figures 13, 14 and 15). Shielding blocks were removed to fa- cilitate the bulk removal of the PBX-M Computer Infrastructure device. A subcontractor team, Project Business and Financial Computing Enhancement Corporation and the De- In FY01 a decision was made to re- commissioning and Environmental Man- place PPPL’s legacy business application agement Company, removed the device systems and mainframe with a mid-level between June and August 2003. More Enterprise Resource Planning Business than 352 tons of metal was recycled dur- Computing System from Microsoft’s ing this phase of the project in a total of Great Plains Software. Business Manage- 19 shipments. The ﬁ nal shipment, the ment International, a consulting ﬁ rm and reseller of Great Plains Software, was contracted to implement the new system, which utilizes client-server technology running on Microsoft’s Windows 2000

Figure 13. The Poloidal Beta Experiment-Modiﬁ cation before (left) and during (right) dis- assembly.

Figure 14. The PBX-M with torque frame and upper shelf removed.

122 Figure 15. The PBX-M test cell following the completion of its removal.

Server and SQL Server 2000 as the da- over the internet. The project remains on tabase management system. Implementa- track for fi nal cut-over and acceptance tion commenced in early F02. After com- during the second quarter of FY04. pleting a detailed specifi cation, it became clear that a higher degree of customiza- Cyber Security tion than originally anticipated would Computer security at PPPL continues be required to meet DOE’s requirements to be an important issue. The number of and PPPL’s business needs. known machines worldwide, which have In fi scal year 2003 signifi cant prog- been infected by both worms and viruses ress was made. Modules that could be has grown to the hundreds of thousands. launched in a “stand-alone” manner were Every minute of every day the PPPL fi re- released for general use. These included wall drops attempted connections num- modules for web-generated requisitions, bering in the hundreds. Our automated monthly timesheets, and the Micromain fi rewall virus protection is also very busy, Corporation MS2000 Facilities Mainte- picking off nearly one hundred e-mail at- nance Management System. Most oth- tached viruses daily. Much of the effort er modules were delivered and accepted in the cyber security area in FY03 was by PPPL Business Operations, including targeted at addressing computer securi- those for managing projects and budgets, ty alerts, installing the latest patches, and procurement, accounts payable, stock- ensuring that all users have the latest vi- room, time and labor reporting, asset rus protection. management, excess property and spare PPPL had no detected cyber securi- parts, fi xed assets, petty cash, and phone ty breaches in FY03. However, the effort expenses. Remaining to be completed to keep viruses and worms from infect- in FY04 are modules for general ledger, ing PPPL systems was signifi cant. A ma- purchase cards, and the web travel sys- jor initiative utilizing Microsoft’s Group tem. Additionally in FY03, the “Anyview Policy was undertaken to assure systems Browser” was implemented as the prima- are patched properly and managed by the ry tool to access Business Systems data PPPL domain, so that future Windows

123 vulnerabilities can be patched more effec- Currently PPPL is collaborating with the tively and effi ciently. An internal policy Naval Research Laboratory on the fabri- was implemented to require all Windows cation of a multi-window device, which systems at PPPL to be centrally managed, will be tested at the Electra KrF Laser Fa- unless specifi cally exempted by supervi- cility. sory approval. Commercial site fi ltering software, Miniature Integrated Websense, was enabled in FY03. Addi- Nuclear Detection System tionally a commercial password manage- Interest in the PPPL Miniature In- ment tool, P-Sync, was implemented, to tegrated Nuclear Detection System allow users to seamlessly change and syn- (MINDS) for Homeland Security pur- chronize numerous passwords. poses has been strong over the past year with approximately $250 K of funds be- Work For Others ing provided to PPPL by Picatinny Arse- Electron Beam Transmission nal for the development of the MINDS Window (“Hibachi”) for IFE technology. The system is designed for During this past year signifi cant prog- rapid and accurate detection and iden- ress was made in the development of tifi cation of radionuclides that could an electron beam transmission window be deployed in a radiological weap- for use in a repetitively pulsed e-beam on (i.e., dirty bomb). MINDS was test- pumped laser for Inertial Fusion Energy ed in a variety of confi gurations, includ- (IFE) development. The PPPL electron ing the entrance of a radiological facility beam transmission window employs nov- and outside a cargo container. The sys- el components, which include single-crys- tem performed exceedingly well. A dem- tal silicon and nanocrystalline diamond. onstration held at PPPL in August 2003 The window has been successfully tested for law enforcement and various trans- at PPPL and at the Naval Research Lab- portation authorities led to an invitation oratory’s Electra KrF Laser Facility. The by representatives of the New York City silicon nanocrystalline diamond window Metropolitan Transportation Authority- is a robust device, which provides great- Bridge and Tunnel Authority to deploy er than 80% electron beam transmission MINDS at the Holland Tunnel. This test effi ciency in the 150 to 750-keV range. is being planned for FY04.

124 Environment, Safety, and Health

he Princeton Plasma Phys- improvement over the 19.35 and ics Laboratory’s (PPPL) Envi- 89.03 averages for FY02 and FY01, T ronment, Safety, and Health respectively, and was below the av- (ES&H) performance continued to show erage for U.S. Department of Ener- signifi cant improvement in each of three gy (DOE). key occupational injury indicators during FY03: Days Away/Restricted/Trans- The second annual PPPL “Safety Fo- ferred (DART) Case Rate, Total Record- rum” was held in October 2002. During able Case (TRC) Rate, and Cost Index. the Forum, workers identifi ed signifi cant The following are some highlights of ES&H issues and provided suggestions the improved safety performance experi- for improvement. In addition to con- enced in FY03: tinuing ES&H initiatives that were begun in FY02, the following actions were • The number of total recordable in- taken in FY03 to improve PPPL ES&H jury and illness cases was reduced performance: 50% in FY03 compared with FY02, and by almost 80% compared with • PPPL hosted a comprehensive Occu- FY01 (Figure 1). pational Safety and Health Adminis- • The PPPL Cost Index average of tration (OSHA) inspection visit for 4.01 for FY03 marked a signifi cant industrial and worker safety.

Number of Recordable Injuries 0 01 02 03 Fiscal Year Figure 1. Princeton Plasma Physics Laboratory recordable injuries versus ﬁ scal year. The number of injuries decreased by almost 80% between FY01 and FY03.

125 • The Princeton Plasma Physics Lab- throughs to examine workplace oratory hosted an inspection vis- safety programs. it by the Nuclear Regulatory Com- • Publication of Lab-wide ES&H mission (NRC) for radiation safety. Newsletters that enhanced employ- • An internal OSHA “competent ee awareness of selected worker safe- person” program was developed to ty and health issues. designate individuals who can act • Facility infrastructure improve- in this role for PPPL construction ments designed to improve work- projects. The competent person is place lighting, walking surfaces, and defi ned as the person who, by virtue safety-related signage. of formal training and experience, can recognize existing and predict- PPPL worked with DOE’s Princeton able safety hazards and has the au- Area Offi ce to develop and implement thority to take prompt corrective a comprehensive plan and schedule for action. the assessment of ES&H functions at • Increased OSHA-related training PPPL. The resulting Assessment Sched- opportunities were provided for ule integrates a variety of oversight activ- PPPL staff members. ities ranging from DOE surveillances to Quality Assurance Audits to internal self- Expansion and refi nement of the • assessments. The schedule is used to help Lab-wide “Job Hazard Analysis” evaluate PPPL’s overall Integrated Safe- program. ty Management performance, and sub- • Performance of more than two sequently to determine what assessments dozen Management Safety Wak- are warranted for future years.

126 Applied Research and Technology Transfer

he transfer of technology to pri- to industry, where further development vate industry, academic institu- is required before a formal collaboration T tions, and other federal laborato- can begin. In addition to the above tech- ries is one of the missions of the Princeton nology transfer mechanisms, the PPPL Plasma Physics Laboratory (PPPL). The Technology Transfer Offi ce encourages Laboratory is currently working with a the development of technologies that are number of partners in scientifi c research potentially relevant to commercial inter- and technology development. These col- ests. These projects are funded by PPPL laborations are Cooperative Research and as Laboratory Program Development Ac- Development Agreements (CRADAs) or tivities. Work For Others (WFOs) projects and The PPPL Technology Transfer Offi ce primarily involve applications of science works closely with the Laboratory’s Bud- and technology developed for PPPL’s fu- get Offi ce and with the Princeton Uni- sion program. In addition to CRADAs versity Offi ce of Research and Project and WFOs the Laboratory also uses Li- Administration (ORPA). PPPL technol- censing Agreements, Personnel Exchang- ogy is licensed through ORPA, and PPPL es, and Technology Maturation Projects inventions are processed through ORPA. to promote the transfer of PPPL technol- The Laboratory works closely with the ogy. University for the patenting and protec- A CRADA, which is a contractual tion of PPPL intellectual property. agreement between a federal laboratory and one or more industrial partners, enables industry and PPPL researchers Small Business Innovative to work on programs of mutual inter- Research Workshop est. Costs and project results are gener- On August 21, 2003, the PPPL Tech- ally shared between PPPL and the part- nology Transfer Offi ce hosted a one-day ner. Work for Others arrangements may workshop for small businesses interested involve either federal or non-federal in the Small Business Innovative Research partners. The partners pay for the work (SBIR) Program and the Small Business performed at PPPL. In the Personnel Technology Transfer (STTR) Program. Exchange Program, researchers from in- The workshop, which was jointly spon- dustry assume a work assignment at the sored by the Federal Laboratory Con- Laboratory, or PPPL staff may visit the sortium and the New Jersey Technolo- industrial setting. In a Technology Mat- gy Council (NJTC), attracted more than uration Project, a Laboratory research- 125 participants (Figure 1). The topics er may work on technologies of interest included:

127 Figure 1. Attendees gathering literature at the Small Business Innovative Research Work- shop held at PPPL in August 2003.

• An overview of the SBIR/STTR • Assistance available from Princeton programs. University on SBIR/STTR propos- • Services available through the NJTC als, with examples of successfully for New Jersey businesses. commercialized University technologies. • Information on the U.S. Depart- ment of Energy’s SBIR programs. Legal experts provided an overview of • The Navy’s SBIR program at Lake- intellectual property issues such as pat- hurst Naval Air Warfare Center. ents, trade secrets, copyrights and trade- • The Army’s SBIR programs at Pica- marks. Other topics included govern- tinny Arsenal and at Fort Mon- ment rights and legal issues related to mouth. intellectual property with respect to SBIRs, STTRs, and CRADAs, and gov- • Collaborative opportunities avail- ernment contracts in general. able at the Princeton Plasma Phys- ics Laboratory. Micro Air Vehicles An overview of training, resources, • During FY03, work continued on and free consultations available from PPPL’s Micro Air Vehicles (MAV) project the Technology Commercialization in support of the Naval Research Labora- Center of the New Jersey Small tory (NRL) Micro Air Vehicle Program. Business Development Center. The Naval Research Laboratory’s MAV • How to write effective SBIR and Program involves fundamental research STTR abstracts. and development on the unconvention-

128 al aerodynamics of miniature air vehicles capability. A second, smaller prototype of and feasibility demonstrations of mis- the TWC was designed and will be built sion-useful MAVs. in FY04 utilizing more sophisticated ma- One effort focused on a technolo- terials. It will have enhanced control in gy demonstration of the Samara con- both travel modes, and testing will begin cept. The Samara combines the slow fl y- next year. Micro Air Vehicle experimen- ing and near vertical ascent capabilities of tal research was coupled with ongoing rotary wing operation with the fast, ef- computational fl uid dynamics and fl ight fi cient fl ight of fi xed wing aircraft. Dur- control system simulations that are con- ing FY03, new automatic control systems tinuing at NRL. were investigated for the Samara aircraft, including mass shifting in response to Miniature Integrated very sensitive airspeed instrumentation. Nuclear Detection System The Samara mass shifting system will be During FY03, PPPL scientists con- tested in FY04. tinued development of the Miniature In addition to the Samara project, Integrated Nuclear Detector System much work was done in FY03 on the (MINDS) (Figure 3), which is designed Tandem-winged Clapper (TWC) (Figure to detect and identify specifi c radionu- 2) — a vehicle capable of multiple modes clides for counter terrorism. The MINDS, of locomotion. A TWC was designed which was supported by funding from and built. This prototype exhibited con- Picatinny Arsenal during FY03, would trolled fl ight in addition to ground travel be used by Police, security personnel, the

Figure 2. Dave Cylinder holds the latest version of the Tandem- winged Clapper. The new model has an enhanced control system and is constructed with composite materials. The inserts going from left clockwise show: (1) a close up of the motor and transmission, (2) the micro air vehicle with its wings “clapped” together, and (3) with its wings in the open position.

129 Figure 3. Miniature Integrated Nuclear Detection System (MINDS) conceptual conﬁ guration.

National Guard, the Coast Guard, and PPPL researchers are working with fac- other agencies involved in homeland se- ulty and students from Rutgers Univer- curity or transportation rule compliance. sity’s Center for Advanced Information The MINDS could detect potential nu- Processing (CAIP) to develop computer clear threats from a weapon of mass de- hardware and detection algorithms. Re- struction or from nuclear contamination, searchers are combining PPPL’s library such as a “dirty bomb.” The objective is of the radionuclide spectra with CAIP’s to detect and identify nuclear material en- advanced neural-network-based detec- tering a site, passing through a toll booth, tion software known as the Vigilant De- placed inside of a shipping container, or cision Machine (VDM). The software is hidden in other ways, under realistic con- capable of learning the speciﬁ c signals as- ditions. The full system, which employs sociated with various radionuclides and mostly off-the-shelf components, will be distinguishing those signals from back- capable of detecting X-rays, soft gam- ground noise and other interference. mas, gammas, and neutrons. A major fea- VDM software has been proven to detect ture is the ability to compare the ener- rare events amidst complex signals found gy spectrum of the detected radionuclide in real-world environments. with the spectrum of particular radiolog- An initial proof-of-principle demon- ical materials that might be used in weap- stration was performed in August 2002, ons. The MINDS can be programmed to in which MINDS demonstrated the de- respond only to those signatures, thus tection of a small quantity of radionu- eliminating false positive alarms resulting clides in a stationary shipping contain- from the movement and transportation er. On August 6, 2003, MINDS’ ability of approved radionuclides, such as med- to detect similar material in a moving ve- ical and industrial shipments. The pres- hicle was demonstrated to representatives ence of false positives is a major concern of Picatinny Arsenal, the New York/New of security personnel. Jersey Port Authority, the New Jersey Of-

130 ﬁ ce of Counter Terrorism, the Rutgers Center for Advanced Information Pro- cessing, the New York City Metropol- itan Transportation Bridge and Tunnel Authority, and other State and munici- pal representatives. Discussions are currently underway with parties interested in licensing the technology for commercial development.

Plasma Sterilization Experiment Hundreds of billions of plastic food and beverage containers are manufactured each year in the U.S. All of these packages must undergo sterilization, which at Figure 4. John Schmidt, lead scientist for present is done using high temperatures PPPL’s Plasma Sterilization Experiment, or chemicals. Both of these methods have with the apparatus. drawbacks. Chemicals often leave a residue that can affect the safety and taste of the ry where technicians determine the num- product and produce undesirable waste. ber of spores killed in the process. Heat is effective and suffi ciently rapid, but Fusion experiments at PPPL have gen- necessitates the use of costly heat-resistant erated plasmas with temperatures in the plastics that can withstand sterilization hundreds of millions of degrees centi- temperatures. Consequently it would be grade. For killing spores, the PPPL re- of great benefi t if a new method could be searchers start with “low-temperature” found that eliminated the need for chem- hydrogen plasmas in the range of 50,000 icals or heat-resistant plastics. degrees centigrade. At that temperature, During FY03, a team of PPPL scien- the hydrogen ions are moving much too tists conducted preliminary small-scale slowly to kill spores quickly. Rapidly puls- experiments studying plasma steriliza- ing a 50-kilovolt potential between the tion. The researchers modifi ed old equip- sphere and the vacuum chamber solves ment that had once been used to study the problem. The sphere is charged neg- radio-frequency (rf) waves for fusion ap- atively and the vessel is at ground. Un- plications. It consists of a vacuum cham- der these circumstances, the positively ber equipped with an radio-frequency charged hydrogen ions accelerate toward source (Figure 4). A brass sphere mea- the sphere in pulses energetic enough for suring one inch in diameter is mounted the ions to pierce the hard outer shell and at the center of the chamber. In prepa- soft inner core of the spores. These high- ration for experiments, the sphere is re- energy hydrogen ions stop very quickly moved and sent to a commercial biolog- and consequently deposit all their ener- ical testing laboratory where a known gy over a very small distance, a few mi- number of spores of bacillus subtilis, a crons, which, as it turns out, is the size of nonpathogenic microbe commonly used the spores. So relatively modest currents as a standard in lab testing, are placed on of energetic hydrogen ions can do a large its surface. Following an experiment, the amount of damage inside the spores by sphere is returned to the testing laborato- destroying their DNA.

131 Figure 5. Shown is an example of the spores Figure 6. Shown is a scanning electron mi- used in the plasma sterilization experiment. croscope image of a small group of bacillus The image, made by a scanning electron subtilis var Niger spores magniﬁ ed approxi- microscope, is of bacillus subtilis var Ni- mately 13,500 times. The image shows that ger spores magniﬁ ed approximately 1,700 the spores are approximately 1 μm long and times. It illustrates the typical spore density approximately 0.5 μm in diameter. on the surface of the brass sphere that is inserted into the sterilization apparatus, and shows that the spores are fairly evenly dis- Completion Date: September 30, tributed over the surface to be sterilized. 2003

Title: Sterilization of Liquid Foods Experiments during FY03 employed 4,000 10-microsecond pulses, which re- Sponsor: U.S. Department of Agri- duced the population of live spores by a culture factor of 100-1,000 — the kill ratio (Fig- Scope: The purpose of this project is ures 5 and 6). Further experimentation is to develop new pasteurization methods needed to conﬁ rm the number of 10-mi- that use radio-frequency (rf) waves and crosecond pulses necessary to reach the microwave heating. These heating tech- required kill ratios for relevant microbes. niques, also used to warm plasma in a fu- It is estimated that a few seconds’ pro- sion device, are being tested for pasteur- cessing time per container would make izing raw liquid foods such as eggs, fruit the system feasible for the assembly line. juices, and milk. Radio-frequency waves offer advantages over the traditional pas- Work For Others teurization method of directly heating Other Work for Others projects fund- raw liquid foods. The direct method of- ed during FY03 included: ten heats foods unevenly, possibly resulting in incomplete pasteurization in low- Title: Experimental and Theoretical er temperature regions and in denaturing Studies of Nonneutral Plasmas foods in overheated regions. Using radio- Sponsor: Ofﬁ ce of Naval Research frequency waves in the appropriate wave- Scope: This program includes a theo- length may allow pasteurization without retical and experimental program in criti- heating liquid foods to temperatures that cal problem areas related to the equilibri- cause food deterioration. um, stability, and nonlinear properties of Start Date: October 1, 1997 nonneutral plasmas. Completion Date: September 30, Start Date: April 1, 1996 2003

132 Title: Low-frequency MHD Waves in perconducting Tokamak Advanced Re- the Magnetosheath-Magnetopause search (KSTAR) device. KSTAR is the Sponsor: National Science Founda- fl agship project of the Korean National tion Fusion Program that was launched offi - cially in January, 1996. The KSTAR de- Scope: This program involves the sys- vice will be built at the National Fusion tematic study of the generation, propa- R&D Center at the Korean Basic Science gation, and structure of low-frequency Institute in Taejon, Republic of Korea. MHD waves and their effects on plasma transport in the magnetosheath-magne- Start Date: October 1, 1999 topause region for quasi-perpendicular Completion Date: November 30, bow shocks. 2003 Start Date: September 15, 1999 Title: Novel Materials for Electra’s Completion Date: May 31, 2003 “Hibachi” Electron Beam Windows Sponsor: Naval Research Laboratory Title: Magnetic Reconnection Exper- iment Scope: Study, design, and produce thin “hibachi” windows fabricated from Sponsor: National Aeronautics and silicon or other novel materials for the Space Administration Electra KrF laser system and perform a Scope: A basic plasma physics research systems engineering study for Electra. facility, the Magnetic Reconnection Ex- Start Date: October 1, 2000 periment (MRX), is studying the phys- Completion Date: December 31, ics of magnetic reconnection — the to- 2003 pological breaking and reconnection of magnetic fi eld lines in plasmas. Scientists Title: Raman Pulse Compression of hope to understand the governing prin- Intense Lasers ciples of this important plasma physics process and gain a basic understanding of Sponsor: Defense Advanced Research how it affects plasma characteristics such Projects Agency as confi nement and heating. The results Scope: A moderately intense, but long, of these experiments will have relevance laser pulse can be scattered into short, to solar physics, astrophysics, magneto- very intense counter-propagating puls- spheric physics, and fusion energy re- es in plasma through a variety of related search. mechanisms. The simplest and most effi - Start Date: October 1, 1995 cient method is the well-studied stimulated Raman backscatter effect. In prin- Completion Date: September 30, ciple, fl uences tens of thousands of times 2003 higher can be handled in plasma, making feasible signifi cantly more intense lasers. Title: Korea Superconducting Toka- In a collaboration involving the Univer- mak Advanced Research, Phase II sity of California, Berkeley, and Prince- Sponsor: Korean Basic Science Insti- ton University, scientists at the Princeton tute Plasma Physics Laboratory are assess- Scope: The Princeton Plasma Physics ing the practical realization of the plas- Laboratory is coordinating a U.S. team ma-based pulse compression schemes. in supporting the design of the Korea Su- Preliminary experimental results show

133 apparent amplifi cation of the counter- Completion Date: February 28, 2004 propagating wave. Title: Vacuum Ceramic Multi-Win- Start Date: October 1, 2000 dow in Titanium Flange Completion Date: March 16, 2004 Sponsor: Institute for Plasma Re- Title: Energy Transport and Dissipa- search, Gujarat, India tion of Electromagnetic Ion Cyclotron Scope: The Institute for Plasma Re- Waves in Magnetosphere/Ionosphere search (IPR) is enhancing its capability Sponsor: National Aeronautics and on the SST1 Tokamak in Gujarat, India, Space Administration and has contacted PPPL to fabricate and Scope: Electromagnetic ion cyclotron supply two multi-channel, ceramic vac- waves in plasmas are generated by elec- uum windows. It is intended that PPPL tron-beam driven instabilities. These staff will work with the cognizant staff at waves play an important role in mag- IPR to determine the fi nal confi gurations netosphere-ionosphere coupling. They of the ceramic window fl anges in order are thought to be responsible for heat- to complete fabrication drawings, pro- ing ionospheric ions, modulating au- cure the necessary materials and servic- roral electron precipitation, populating es, and to assemble and test the fi nal ce- the magnetosphere with energetic heavy ramic window assemblies at PPPL before ions during substorms, as well as produc- shipment to IPR. ing parallel electric fi elds and electrostatic Start Date: October 1, 2002 shock signatures. This program involves Completion Date: September 30, the development of solutions to full wave 2003 equations for electromagnetic ion cyclotron waves using a nonlocal theory which Title: Testing of the Detritiation of the includes kinetic effects and ionospheric JET Tiles by Heating with the Oxy-Gas collisions. The solutions can provide spe- Burner cifi c predictions of global electromagnet- Sponsor: United Kingdom Atomic ic ion cyclotron wave structure, wave po- Energy Authority, England larization, and Poynting fl uxes which are Scope: The United Kingdom Atom- observables that can be compared direct- ic Energy Authority wants to investigate ly with spacecraft measurements. the removal of co-deposited tritium from Start Date: October 1, 2000 the Joint European Torus (JET) graph- Completion Date: April 30, 2003 ite tiles employing localized heating. In general the tile samples will fi rst be char- Title: Self-consistent Model for Re- acterized for tritium content and tritium gions of Downward Auroral Current depth profi le. After such analysis, the tile Sponsor: National Science Founda- sample will be subjected to direct heat tion from a burner to liberate the co-deposit- Scope: The objective of this program is ed tritium from the tile. After the appli- to develop a self-consistent understand- cation of localized heat, the tile will be re- ing of the plasma and fi eld properties of analyzed to determine the effectiveness of downward auroral currents. the techniques employed. Start Date: March 13, 2002 Start Date: October 1, 2002

134 Completion Date: December 20, Title: Accretion onto Massive Black 2003 Holes in Low-luminosity Galactic Nu- clei Title: Kinetic Ballooning Instability as Sponsor: National Aeronautics and a Mechanism for Substorm Onset in the Space Administration Near Earth Plasma Sheet Scope: Most galaxies in the universe Sponsor: National Aeronautics and contain supermassive black holes at Space Administration their centers; and yet most galactic nu- Scope: The objective of the project clei emit very little radiation indicative is to study the onset mechanism of sub- of active accretion. The purpose of this storms which occur in the near-Earth work is to investigate this issue using plasma sheet region of the magneto- low-radiative-effi ciency accretion fl ow sphere. Theoretical predictions will be models, including advection-dominat- compared with satellite observations to ed and convection-dominated accretion clarify unresolved physics issues. fl ows. Start Date: October 1, 2002 Start Date: October 1, 2002 Completion Date: May 31, 2004 Completion Date: August 14, 2004

Title: Concept Exploration of Nov- Title: Low Power Hall Thruster el Hall Thruster Confi gurations: Staged Sponsor: (U.S.) Air Force Offi ce of Hall-Ion Thruster with Cylindrical Con- Scientifi c Research fi guration Scope: Hall thrusters hold consider- Sponsor: Defense Advanced Research able promise for propellant savings for Projects Agency space vehicles. The annular design of Scope: The objective of this project is the conventional Hall thruster, howev- to explore several novel plasma propul- er, does not naturally scale to low pow- sion confi gurations with an aim to eval- er. This project is exploring a family of uating potential performance, including Hall thrusters of cylindrical, rather than high-power (10-20 kW), mid-power (1- annular design, with a cusp-like magnet- 5 kW), low power (under 100 W), mod- ic fi eld, making use not only of the cy- erate specifi c impulse (1,500-2,500 s), lindrical design, but of other advanced high specifi c impulse (more than 3,000 features such as emissive segmented elec- s), and desirable features such as throt- trodes and central localizing of the cath- tling, lifetime, or variable thrust. ode neutralizer. Start Date: October 1, 2002 Start Date: October 1, 2003 Completion Date: September 30, Completion Date: September 30, 2003 2006

135 136 Patents and Invention Disclosures

Patent Application Miniature Nuclear Detection System (MINDS) — Charles Gentile, George Ascione, Andrew Carpe, Stephen Langish, and John Parker

Provisional Patent Radio Frequency Electric Field Pasteurization Chamber — Christopher Brunkhorst, David J. Geveke, and Andrew B.W. Bigley

Invention Disclosures Feedback Elimination in Hearing Aids and Sound Systems — Lewis Meixler

Development of Thin Films for the Mitigation of Particulate Associated with Biological and Industrial Hygiene Hazards — Margaret E. Lumia and Charles A. Gentile

Massively Parallel Interactive Data Language (MPIDL) — Dana Mastrovito

Out-board ‘Ohmic Induction’ Coil for Low-aspect-ratio Toroidal Plasma Start-up — Masayuki Ono and Wonho Choe

Silicon/Nanocrystalline Diamond Electron Beam Transmission Window — Charles A. Gentile, Robert F. Parsells, and James E. Butler

Collaborative Scientiﬁ c visualization — Eliot Feibush, Scott Klasky, and Douglas McCune

Use of Multiple Frequency Pumps in Optimizing Pulse Compression — Alexey Balakin, Gennady Fraiman, Nathaniel J. Fisch, and Vladmir Malkin

Radio Frequency Electric Field Pasteurization Chamber — Christopher Brunkhorst, David J. Geveke, and Andrew B.W. Bigley

137 Current Drive in a Ponderomotive Potential with Sign Reversal — N.J. Fisch, J.M. Rax, and I.Y. Dodin

Electrostatic Dust Detector — Charles Skinner

Contaminated Surface Cleaner — John Desandro, Mike Kalish, Jim Kukon, and Mike Anderson

A New Instrument for Simultaneous Measurement of Toroidal and Poloidal Plasma Rotation Velocity Proﬁ les — M. Bitter, K.W. Hill, L. Roquemore, B. Stratton, S.G. Lee, J.E. Rice, and E. Marmar

138 Graduate Education

Program in Plasma Physics graduate students for academic year 2003-2004. Standing left to right: Alexey Kuritsyn, Jill Foley, Stefﬁ Diem, Phil Marfuta, Seunghyeon Son, Adam Sefkow, Moses Chung, Tom Kornack, Dan Raburn, Ilya Dodin, Tim Gray, Tom Jenkins, Ethan Schartman, Kyle Morrison, Nate Ferraro, Tim Stoltzfus-Dueck, Barbara Sarfaty, Administrator. Kneeling left to right: Dave Smith, Mahmood Miah, Yansong Wang, Pat Ross, Ian Parrish, Yang Ren, Prateek Sharma, Wei Liu, and Weihua Zhou.

raduate education at the Prince- (M.S.E.) or Doctoral (Ph.D.) degrees are ton Plasma Physics Laborato- given through the departments of Astro- Gry (PPPL) is supported through physical Sciences, Chemical Engineer- the Program in Plasma Physics and the ing, Chemistry, Civil Engineering, Com- Program in Plasma Science and Tech- puter Science, Electrical Engineering, nology. Students in the programs receive Mechanical and Aerospace Engineering, advanced degrees from Princeton Uni- and Physics. versity. In the Program in Plasma Phys- ics, Doctoral (Ph.D.) degrees are given Program in Plasma Physics through the Department of Astrophysi- The Princeton University Plasma cal Sciences while in the Program in Plas- Physics Laboratory supports graduate ma Science and Technology, Masters education through the Program in Plas-

139 First year graduate students from left to right are: Nate Ferraro, Steffi Diem, Pat Ross, Yansong Wang and Dan Raburn. ma Physics in the Department of Astro- ma Physics, holding between them three physical Sciences of Princeton Universi- U.S. Department of Energy Magnetic ty. Students are admitted directly to the Fusion Energy Science Fellowships, one Program and are granted degrees through National Defense and Science Engineer- the Department of Astrophysical Scienc- ing Graduate Fellowship, and one Hertz es. With more than 215 graduates since Fellowship. 1959, the Program has had a signifi cant Five new students (Table 1) were ad- impact on the fi eld of plasma physics, mitted in FY03, one from China and providing many of today’s leaders in the four from the United States. Three stu- fi eld of plasma research and technology dents graduated (Table 2) during the in academic, industrial, and government year, two accepting positions at Lawrence institutions. Livermore National Laboratory and Los Both basic physics and applications are Alamos National Laboratory. One stu- emphasized in the Program. There are dent won the prestigious American Phys- opportunities for research projects in the ical Society Congressional Fellowship physics of the very hot plasmas necessary and is working in the offi ce of Senator for controlled fusion, as well as for proj- Bingaman (New Mexico) in Washing- ects in solar, magnetospheric and iono- ton, D.C. spheric physics, plasma processing, plasma thrusters, plasma devices, nonneutral Program in Plasma Science plasmas, lasers, materials research, and in and Technology other important and challenging areas of Applications of plasma science and plasma physics. technology meld several traditional scien- In FY03, there were 35 graduate stu- tifi c and engineering specialties. The Pro- dents in residence in the Program in Plas- gram in Plasma Science and Technology

140 Table 1. Students Admitted to the Program in Plasma Physics in FY03.

Student Undergraduate Institution Major Field

Stephanie J. Diem University of Wisconsin, Madison Physics Nathaniel M. Ferraro Dartmouth College Physics Daniel L. Raburn University of California, Berkeley Physics Patrick W. Ross Brigham Young University Physics Yansong Wang University of Science and Plasma Physics Technology, China

Table 2. Recipients of Doctoral Degrees in FY03.

Clark, Daniel Thesis: Investigations of Raman Laser Ampliﬁ cation in Preformed and Ionizing Plasmas Advisor: Nathaniel J. Fisch Employer: Lawrence Livermore National Laboratory

Rosenberg, Adam Thesis: Ion Absorption of the High Harmonic Fast Wave in the NSTX Advisors: Jonathan Menard and J. Randy Wilson Employer: American Physical Society Congressional Fellowship Senator Bingaman’s Ofﬁ ce (New Mexico)

Zaharia, Sorin Thesis: 3-D Magnetospheric Structures and Energetic Particle Injection Advisor: C.Z. Cheng Employer: Los Alamos National Laboratory

(PPST) provides strong interdisciplinary eous lasers, in which the lasing medium support and training for graduate stu- is plasma. X-ray laser research is promi- dents working in these areas. The scope nent in the PPST. Another example is fu- of interest includes fundamental studies sion energy for which the fuel is a high- of plasmas, their interaction with surfac- temperature plasma. Lower temperature es and surroundings, and the technolo- plasmas are used for a growing number of gies associated with their applications. materials fabrication processes, including Plasmas are essential to many high- the etching of complex patterns for mi- technology applications, such as gas- cro-electronic and micro-optical compo-

141 nents and the deposition of tribological, dents received Ph.D. degrees from their magnetic, optical, conducting, insulat- respective departments. ing, polymeric, and catalytic thin-fi lms. Professor R. Rosner was the distin- Plasmas are also important for illumina- guished speaker at the PPST public lection, microwave generation, destruction ture series held to inform the Princeton of toxic wastes, chemical synthesis, space community of contributions made by propulsion, control system theory and plasma science and technology to our so- experiment, and advanced-design parti- ciety. In a talk entitled, “Burning Stars in cle accelerators. One’s Offi ce: The Physics of Astrophysi- The PPST provides support for cal Nuclear Flames,” Dr. Rosner, Distin- M.S.E. and Ph.D. students who con- guished Service Professor, Astronomy and centrate on a specifi c research topic Astrophysics and Physics Departments, within the fi eld of plasma science and University of Chicago, described simi- technology, while acquiring a broad larities between laboratory-scale combus- background in relevant engineering and tion fronts and processes in supernova. scientifi c areas. Departments in the pro- To maintain this strong graduate program are Astrophysical Sciences, Chem- gram, increased efforts were made to de- ical Engineering, Chemistry, Civil En- velop appreciation for plasma physics in gineering, Computer Science, Electrical Princeton undergraduates. Through a Engineering, Mechanical and Aerospace summer internship program, fi ve Prince- Engineering, and Physics. In fi scal year ton undergraduates worked on plasma- 2003, eleven graduate students received related projects. One summer intern, a support from the PPST during the ac- history major investigating seminal ideas ademic year and/or summer. They co- in fusion plasma physics, was able to get authored more than a dozen refereed one of the last interviews given by Dr. publications. Four PPST-supported stu- Edward Teller.

142 Science Education

he goals of the Science Educa- instruction using an inquiry-based ap- tion Program (SEP) are to pro- proach to learning, and (3) to improve T vide a comprehensive portfolio the scientiﬁ c literacy of the community of initiatives that use the unique resourc- at large. These initiatives are led by SEP es of the Princeton Plasma Physics Labo- staff in conjunction with PPPL volun- ratory (PPPL) along with a plasma-based teers, master teachers, and local educa- education strategy to create signiﬁ cant tion experts. learning opportunities for undergraduate college students and K-12 teachers Plasma Science and students. Through these opportuni- Education Laboratory ties, the SEP strives to: (1) contribute to The center of all SEP activities is the the training of the next generation of sci- Plasma Science Education Laboratory entists and engineers, (2) to collaborate (PSEL). A fusion of research between ed- with teachers on ways to improve science ucation and plasma science, this unique

Plasma

The Science Education program uses a plasma-based education strategy that recognizes that plasmas are superb for generating questions, stimulating curiosity, and increasing personal relevance of learning for students of all ages. (This graph is from Master Teacher S. Gersh- man’s American Physical Society Division of Plasma Physics Meeting presentation titled “The Use of a Glow Discharge Source for Teaching Introductory Physics.”)

143 The Plasma Science Education Laboratory at PPPL. facility includes a classroom, general lab- other’s work, write papers, and make oral oratory space for educational workshops, and poster presentations. Simultaneous- and areas for advanced plasma physics rely, the PSEL’s open layout for education- search. The experimental activities per- al workshops fosters communication be- formed in the PSEL simulate a research tween participants, master teachers, and environment while remaining primari- student researchers to create a unique ly student centered. Undergraduate and learning environment for teachers and advanced high school students plan all students of all abilities. work, formulate research goals, assemble Research projects conducted in the all apparatus, collaborate with scientists PSEL during FY03 included the study and engineers, critique and evaluate each of dusty plasmas in a DC glow discharge

Photograph of a levitating dust cloud in an argon plasma discharge. The cloud, approximately one centimeter high, is illuminated by a 2.5 mW helium-neon laser.

144 High school research interns from The Peddie School and West Windsor-Plainsboro High School North adjust the laser and gas pressure in the Dusty Plasma Experi- ment. plasma source, the characterization of an Lewis School and a variety of single-day electron cyclotron resonance system for workshops for teachers and students. plasma processing, and the study of the relationship between a plasma double Undergraduate layer and ion transport across a biologi- Research Programs cal cell membrane. In FY03, nine students from the U.S. Two students presented their work Department of Energy’s (DOE’s) Sci- at American Physical Society meetings. ence Undergraduate Laboratory Intern- Dartmouth College Junior Laura Berzak ship (SULI) program and 19 from the presented “A Study of a Striated Positive DOE National Undergraduate Fellow- Column after Ethanol Impurity Injection ship (NUF) program, completed their in an Air DC Glow Discharge” and West summer research at PPPL, other DOE Windsor-Plainsboro High School Se- Laboratories, and U.S. colleges and uni- nior Niraj Sheth presented “Experimen- versities. The DOE Ofﬁ ce of Science tal Investigations of Dust Levitation in a Workforce Development and Ofﬁ ce of DC Glow Discharge.” Additionally, SEP Fusion Energy Sciences support the re- Lead Scientist Andrew Post-Zwicker pre- search programs, respectively. In both sented a summary of SEP research and programs, students attend a one-week in- educational activities in an invited talk, troductory course at PPPL in the basic “Recent Results from the Plasma Science elements of plasma physics, after which Education Laboratory.” they travel to the sites for a nine-week Educational workshops conducted in research project. Student research top- the PSEL during FY03 included the an- ics ranged from “The Development of nual Plasma Camp for high school teach- an Electrostatic Dust Detector for use in ers and Plasma Academy for high school a Tokamak Reactor” to “Wavelet Analy- students. The PSEL also provided labo- sis of Probe Data in DIII-D,” with sci- ratory space for physics classes from The entists and engineers serving as mentors.

145 Select students were given the opportunity in the Fall to present their work at the Annual American Physical Society’s Divi- sion of Plasma Physics Meeting. Pre-college Activities Lewis School Collaboration An ongoing collaboration for students with atypical learning styles of The Lew- is School was formalized with the goal of supplementing the existing physical science curriculum with new topics taught at PPPL in the Plasma Science Education Physics students from The Lewis School Laboratory, including solar and fusion perform a plasma spectroscopy experiment. energy. In FY03, the eleventh grade physics class visited the PSEL throughout the school year designing and building solar- repeated in FY04 and expanded to in- powered devices and learning about re- clude a plasma physics laboratory in the newable energy. school. Energy in the 21st Century Plasma Camp In FY03, a new collaboration with the For the sixth year, high school phys- Academy for the Advancement of Sci- ics teachers from around the country par- ence and Technology in Bergen Coun- ticipated in “Plasma Camp.” At Plasma ty began. High school juniors spent one Camp teachers study plasmas and ways to week at PPPL in the PSEL studying so- weave plasma physics into existing curri- lar energy, hydrogen fuel cells, plasmas, cula. Each year a mixture of new and vet- and fusion energy. The program will be eran teachers work collaboratively on de-

Plasma Camp teacher Duane Nickell (Franklin High School, Indianapolis, In- diana) measures the spectrum from a plasma ball before writing a lesson plan for his high school physics students.

146 veloping new plasma-based lessons and Science Bowl hands-on projects. Twenty-fi ve teams from 20 area schools competed in the New Jersey Re- Scientist-in-Residence gional Competition of the National Sci- In FY03, PPPL continued the Scien- ence Bowl®. This was the eleventh year tist-in-Residence Program for elementa- PPPL hosted the Jeopardy-like tourna- ry schools. A PPPL scientist worked with ment in which all the categories are dis- an entire grade of students for an extend- ciplines of science. Each team is made up ed period of time to increase their scien- of four students, a student alternate, and tifi c literacy and teach scientifi c method- a teacher who serves as an advisor and ology using topics that complement the coach. The Academy for the Advance- school’s existing curriculum. Students ment of Science and Technology in Ber- worked in small collaborative groups gen County won the competition. on a research topic, supported by their teacher and the PPPL scientist. During Trenton Partnership the residency, a variety of activities sup- PPPL has a long tradition of utiliz- porting student projects are used to foster ing the unique resources of the laborato- critical thinking skills, as well as increase ry to aid in the improvement of science understanding of the current topic. This instruction for students and teachers in year, an eight-week “Scientist-in-Resi- the Trenton, New Jersey public school dence” program was conducted for the district. In FY03, PPPL began a collab- fi fth grade of the Woodrow Wilson Ele- oration with Princeton University called mentary School in Westfi eld, New Jersey. “Teaching Math Counts.” The focus of The focus was on the sun, the solar sys- the program is the integration of science, tem, and solar energy. mathematics, language arts, and technol-

Congressman Rush Holt (Democrat, New Jersey 12th District), far left, and the win- ning Science Bowl team from The Academy for the Advancement of Science and Tech- nology, Bergen County, New Jersey.

147 ogy for teachers in grades kindergarten through eighth grade.

Other Activities PPPL supported the New Jersey In- stitute of Technology’s Mount Laurel’s Women in Technology Program. This four-week course is designed to introduce female students to careers in engineering and technology. It is open to students who have completed seventh grade and have at least a B average in mathematics. In FY03, PPPL sponsored stu- High school students from the Douglass dents from Trenton and Burlington area College Summer Science Institute in the schools to attend the program. Plasma Science Education Laboratory. Each year, the Douglass Science Insti- tute Program visits PPPL for a Summer a day of hands-on activities, a laborato- Science Exploration Day. Douglas Col- ry tour, and lunch with female scientists lege offers pre-college women who are in- and engineers. Approximately 40 stu- terested in math, science and engineering dents participate in this event each year.

148 Awards and Honors

2002 PPPL Employee Recognition Award Recipients

Honored by their co-workers for their “personal qualities and professional achievements,” ﬁ fteen PPPL’ers received 2002 Employee Recognition Awards. Along with PPPL Direc- tor Rob Goldston (far right) are the recipients attending the awards ceremony. From left are: (kneeling) Elle Starkman, Patti Wieser, Evelyne Mirville, Scott Gifford, and Goldston; (standing) Jerry Siegel, Ron Davidson, Andrew Post-Zwicker, Ronnie Koon, Nevell Green- ough, John DeSandro, and Steve Langish.

Individual Honors

Marc Cohen Outstanding Co-operative Education Partner Award Drexel University Alumni Association

John DeLooper Distinguished Associate Award U.S. Department of Energy

149 Ilya Dodin Harold W. Dodds Honoriﬁ c Fellowship Princeton University

Nathaniel Fisch Outstanding Mentor U.S. Department of Energy

Hantao Ji Award for Excellence in Plasma Physics Research American Physical Society

Stan Kaye Fellow American Physical Society

John Krommes PPPL Distinguished Research Fellow Princeton Plasma Physics Laboratory

Robert Parsells PPPL Distinguished Engineering Fellow Princeton Plasma Physics Laboratory

Erik Perry Kaul Foundation Prize for Excellence in Plasma Physics and Technology Development Princeton University

Andrew Post-Zwicker Certiﬁ cate of Recognition Sigma Xi, the Scientiﬁ c Research Society Princeton Chapter

Adam Rosenberg Congressional Science Fellowship American Physical Society

Prateek Sharma Thomas H. Stix ’54 Plasma Physics Prize Princeton University

Robert Simmons Engineering and Technology Management Leadership Award American Society of Mechanical Engineers

150 Ronald Strykowsky Kaul Foundation Prize for Excellence in Plasma Physics and Technology Development Princeton University

Masaaki Yamada Award for Excellence in Plasma Physics Research American Physical Society

Laboratory Honors

Gold Award United Way For PPPL’s “Outstanding Service to the People of Our Community”

Honorable Mention Citation U.S. Department of Energy For PPPL’s “Excellence in Project Management” for the Tokamak Fusion Test Reactor Decontamination and Decommissioning

Princeton University physics professor and University Research Board Chair Will Happer and PPPL Director Rob Goldston present the PPPL Distin- guished Research and Engineering Fellow Awards and the Kaul Foundation Prize for Excellence in Plasma Physics and Technology Development during an awards ceremony at the Laboratory. From left are Happer, Engineering Fel- low recipient Robert Parsells, Goldston, Kaul Prize recipients Erik Perry and Ronald Strykowsky, and Research Fellow recipient John Krommes.

151 152 The Year in Pictures

Energy Secretary Spencer Abraham visited PPPL in January with exciting news for the entire fusion community: the U.S. was joining the negotiations for ITER, a major international magnetic fusion research project. The visit included addressing staff and the media, where the Energy Secretary made the announcement, and a tour of the experimental facilities.

At left, PPPL Director Rob Goldston shows the National Spherical Torus Experi- ment to (from left) U.S. Congressman Rush Holt, Energy Secretary Spencer Abra- ham, U.S. Congressman Rodney Frelinghuysen, U.S. Department of Energy Ofﬁ ce of Science Director Raymond Orbach, and Princeton University President Shirley Tilghman.

At right, Secretary Abraham addresses PPPL staff and friends in the Gottlieb Auditorium.

153 PPPL Chief Scientist Bill Tang (far right), joined by Laboratory offi cials and friends, cut the ribbon on the Pilot Topical Computing Facility in October. The goal of the pilot is to determine the best confi guration for a full Topical Computing Facility for the Fusion Ener- gy Science community. The facility will support computing throughout the fusion community, offering a unique capability that joins advanced computing and modeling with theory and experiment to improve advancements in the fi eld of fusion. From left are Oak Ridge National Laboratory’s Lee Berry, PPPL’s Darren Wah, Geophysical Fluid Dynamics Labo- ratory’s Brian Gross, PPPL’s Steve Jardin, PPPL Director Rob Goldston, Lawrence Liver- more National Laboratory’s Bill Nevins, and PPPL’s Doug McCune, Ernie Valeo, Steve Da- vis, and Tang.

PPPL’s Site Protection staff showed off their fi nest gear and gave demonstrations at the Laboratory during Fire Prevention Week, celebrated the second week of Oc- tober. With the theme, “Team UP for Fire Safety,” the fi refi ghters encouraged employees to recognize the role they play in keeping their homes — and workplace — fi re safe. The Lab’s fi refi ghters offered fi re extinguisher training in the Cafeteria Courtyard, as well as distributed handouts about fi re safety and exhibited fi re fi ghting clothing and equipment. PPPL Site Protection staff members Michael Loh (left) and Kevin Rhoades work at the Fire Prevention Week displays.

In October, the Laboratory celebrated “America Recycles Day” with a special program in the MBG Auditorium. The program featured a skit about recycling, as well as a report about PPPL’s performance in recycling and buying recycled- content items in 2002. PPPL’s Thomas McGeachen (left) and Bob Tucker participate in the skit.

154 On December 6, 2002, PPPL Director Rob Goldston delivered his annual “State-of-the- Lab” address to staff, discussing PPPL’s scientiﬁ c programs, internal operations, and the future. “A following wind may be rising,” said Goldston, thanking the Laboratory’s line of “great supporters” in Congress, the Department of Energy, and the White House.

In March, PPPL hosted the U.S. Department of Energy’s Region- al Science Bowl® competition. Twenty-nine teams and more than 40 volunteers participated in this event. PPPL Deputy Director Rich- ard Hawryluk (standing) serves as a science judge while the East Bruns- wick team (at left) takes on the Academy for the Advancement of Science and Technology team from Hackensack.

In June, the Laboratory honored 33 inventors for ﬁ scal year 2002 during the annual Patent Awareness Program Recognition Dinner at Princeton University’s Prospect House. Those attending the dinner and receiving awards were, from left, Charles Gentile, Philip Efthi- mion, Andrew Carpe, David Staack, Yevgeny Raitses, Charles Skinner, John Desandro, Eliot Feibush, Stephen Jardin, Scott Klasky, Erik Perry, George Ascione, John Schmidt, Kenneth Hill, Geoff Gettelﬁ nger, Keith Rule, Robert Parsells, Irving Zatz, and Robert Woolley.

155 A team of PPPL staff and subcontractors safely dismantled and removed the Princeton Beta Experiment-Modiﬁ cation (PBX-M) during the summer. PBX-M, which operated from 1989 to 1994, also operated as PBX from 1985 to 1989 and as the Poloidal Divertor Exper- iment from 1978 to 1985. The cleared space is now ready for the National Compact Stellar- ator Experiment, which is expected to begin operations in 2008. The PBX-M vacuum vessel, loaded onto a ﬂ at-bed truck, is taken from the PPPL site. Insert shows workers securing the vessel for its journey.

In September, Department of Energy Offi ce of Science Director Ray Orbach attended the PPPL On-site Review, which focused on the Laboratory’s vision for the next decade. Facing the camera, from left, are Orbach, Toni Joseph, Director, Offi ce of Laboratory Policy for the Department of Energy Offi ce of Science, and PPPL Director Rob Goldston (standing). At far right with his back to the camera is PPPL Chief Scientist Bill Tang.

156 PPPL Financial Summary by Fiscal Year (Thousands of Dollars) FY99 FY00 FY01 FY02 FY03 Operating Costs Fusion Energy Sciences NSTX $13,737 $18,248 $20,538 $19,894 $25,604 TFTR 3,640 12,101 17,402 14,936 717 NCSX 2,840 3,644 3,156 3,608 3,109 Theory and Computation 5,161 5,823 5,757 6,201 6,749 Off-site Collaborations 9,281 8,342 7,722 7,601 9,121 Off-site University Research Support 697 719 871 742 819 CDX-U 680 876 771 822 743 MRX 221 600 513 462 673 Heavy Ion Fusion 415 513 1,078 1,191 1,410 Next-step Options 1,365 900 771 749 589 Science Education Programs 652 515 593 624 667 Waste Management* – – 3,086 2,790 – ITER 488 – – – 705 Other Fusion 784 1,077 1,369 1,442 1,700 Total Fusion Energy Sciences $39,961 $53,358 $63,627 $61,062 52,606 Environmental Restoration and Waste Mgt $3,564 $3,036 $95 $123 – Advanced Scientiﬁ c Compuing Research 92 21 72 547 437 Basic Energy Sciences 534 608 391 161 79 High Energy Physics 80 98 316 341 181 Safeguards and Security** – – 1,670 1,617 1,623 Science Laboratories Infrastructure – – – 710 679 Other DOE 58 34 120 185 87 Total DOE Operating $44,289 $57,155 $66,291 $64,746 $55,692 Work for Others Federal Sponsors $666 596 1,111 1,424 1,958 Nonfederal Sponsors 1,612 515 596 130 170 Other DOE Facilities 348 150 425 235 103

TOTAL OPERATING COSTS $46,915 $58,416 $68,423 $66,535 $57,923 Capital Equipment Costs NSTX $8,503 $5,532 $2,393 $1,995 $976 TFTR – 1,273 870 34 – Off-site Collaborations 544 655 1,714 2,187 1,817 NCSX – – – – 4,796 All Other Fusion 426 242 917 966 200 All Other 58 1 177 – –

TOTAL CAPITAL EQUIPMENT COSTS $9,531 $7,703 $6,071 $5,182 $7,789 Construction Costs General Plant Projects - Fusion $798 $2,070 $1,533 $2,170 738 General Plant Projects - S&S – – – – 49 Energy Management Projects 15 110 77 64 28 Other DOE Construction (2) 7 – – –

TOTAL CONSTRUCTION COSTS $811 $2,187 $1,610 $2,234 $815 TOTAL PPPL $57,257 $68,306 $76,104 $73,951 $66,527

*Waste Management transferred to the Fusion Energy Sciences Program from Environmental Restoration/Waste Management in FY2001. Waste Management transferred to an indirect funded activity in FY2003. **Safeguards and Security became a direct funded activity in FY2001; funded through overhead prior to FY2001.

157 158 PPPL Organization

Directorate Departments Robert J. Goldston Advanced Projects Director John A. Schmidt, Head Richard J. Hawryluk G. Hutch Neilson, Deputy Deputy Director Off-Site Research William M. Tang Ned R. Sauthoff Chief Scientist Plasma Science and Technology Nathaniel J. Fisch Philip C. Efthimion Associate Director for Academic Affairs National Spherical Torus Experiment John W. DeLooper Martin Peng, Program Director* Associate Director for External Affairs Edmund J. Synakowski, Deputy Prog Dir Masayuki Ono, Project Director Steven M. Iverson Michael D. Williams, Deputy Proj Dir Head, Human Resources Theory Susan E. Murphy-LaMarche William M. Tang, Head Deputy Head, Human Resources Ronald C. Davidson, Deputy Experiment Joel C. Hosea PPPL Director’s Cabinet Engineering and Technical Infrastructure Robert J. Goldston Michael D. Williams Director Business Operations Richard J. Hawryluk Edward H. Winkler Deputy Director Environment, Safety, and Health William M. Tang and Infrastructure Support Chief Scientist John W. Anderson William Happer Chair, Princeton University * from Oak Ridge National Laboratory, Research Board residing at PPPL.

PPPL Stafﬁ ng Summary by Fiscal Year FY99 FY00 FY01 FY02 FY03

Faculty 3 3 3 3 3 Physicists 89 91 97 95 94 Engineers 74 85 82 82 77 Technicians 139 197 210 166 157 Administrative 69 77 73 72 73 Ofﬁ ce and Clerical Support 19 21 20 18 16 Total 393 474 485 436 420

159 160 PPPL Advisory Council

The Princeton Plasma Physics Laboratory Advisory Council advises Princeton University on the plans and priorities of the Laboratory. Members of the Advisory Council are appointed by the Board of Trustees and are chosen from other universities and organizations, and from the Board of Trustees. The Council meets annually and reports to the University President through the Provost.

Dr. Norman R. Augustine Dr. William L. Kruer Lockheed Martin Corporation Lawrence Livermore National Laboratory Dr. David E. Baldwin Dr. Jerry D. Mahlman General Atomics Princeton University Dr. Jonathan M. Dorfan Dr. Barrett Ripin Stanford Linear Accelerator Facility Research Applied Professor Edward A. Frieman Professor Marshall N. Rosenbluth Scripps Institution of Oceanography University of California, San Diego Mr. Robert I. Hanﬂ ing Putnam Hayes & Bartlett

161 162 Publications

*Alekseyev, A.G., Darrow, D.S., *Balakin, A.A., Fraiman, G.M., Fisch Roquemore, A.L., Medley, S.S., Amosov, N.J., and Malkin, V.M., “Noise Sup- V.N., Krasilnikov, A.V., Prosvirin, D.V., pression and Enhanced Focusability in and Tsutskikh, A.Yu., “Application of Plasma Raman Ampliﬁ er with Multi- Natural Diamond Detector to Energetic frequency Pump,” in the Proceedings of the Neutral Particle Measurements on 30th European Physical Society Conference NSTX,” Rev. Sci. Instrum. 74 (March on Controlled Fusion and Plasma Physics 2003) 1905-1908. Presented at the Four- (7-11 July 2003, St. Petersburg, Russia), teenth APS Topical Conference on High Europhysics Conference Abstracts 27A Temperature Plasma Diagnostics (8-10 (European Physical Society, 2003) paper July 2002, Madison, Wisconsin). P-3.66. This conference proceedings is published on CD-ROM. Papers available *§Bader, A., Skinner, C.H., Roquemore, in PDF format at http://eps2003.ioffe. A.L., and Langish, S., “Development of ru/ (as of 12 November 2003). an Electrostatic Dust Detector for use in a Tokamak Reactor,” Rev. Sci. Instrum. *§Balakin, A.A., Fraiman, G.M., 75 (February 2004) 370-375; Princeton Fisch N.J., and Malkin, V.M., “Noise Plasma Physics Laboratory Report PPPL- Suppression and Enhanced Focusability 3866 (September 2003) 24 pp. in Plasma Raman Ampliﬁ er with Multi- frequency Pump,” Phys. Plasmas 10 *Balakin, A.A., Fraiman, G.M., Fisch (December 2003) 4856-4864; Princeton N.J., “Hot Electrons Production in Laser Plas ma Physics Laboratory Report PPPL- Plasmas,” in the Proceedings of the 30th 3824 (June 2003) 9 pp. European Physical Society Conference on Controlled Fusion and Plasma Physics (7- *§Barnard, J.J., Ahle, L.E., Bieniosek, 11 July 2003, St. Petersburg, Russia), F.M., Celata, C.M., Davidson, D.P., Europhysics Conference Abstracts 27A Henestroza, E., Friedman, A., Kwan, (European Physical Society, 2003) paper J.W., Logan, B.G., Lee, E.P., Lund, P-3.82. This conference proceedings is S.M., Meier, W.R., Sabbi, G.-L., Seidl, published on CD-ROM. Papers available R.A., Sharp, W.M., Shuman, D.B., in PDF format at http://eps2003.ioffe. Waldron, W.L., W.R., Qin, H., and Yu, ru/ (as of 12 November 2003). S.S., “Integrated Experiments for Heavy

*First author is from another institution. PPPL co-authors are underlined. †Paper presented at a conference in fi scal year 2003; published in fi scal year 2004. §Submitted for publication in fi scal year 2003; published in fi scal year 2004.

163 Ion Fusion — The Integrated Beam 506. Presented at the 15th International Experiment and the Integrated Research Conference on Plasma Surface Interactions Experiment,” Laser and Particle Beams in Controlled Fusion Devices (PSI-15) (27- 21 (October 2003) 553-560. 31 May 2002, Gifu, Japan).

*Barnes, D.C., Belova, E.V., Davidson, *§Belikov, V.S., Kolesnichenko, Ya. I., R.C., Ishida, A., Ji, H., Milroy, R., Parks, and White R.B., “Destabilization of Fast P., Ryutov, D., Schaffer, M., Steihauer, Magnetoacoustic Waves by Circulating L., Yamada, M., “Field-Reversed Conﬁ g- Energetic Ions in Toroidal Plasmas,” uration (FRC) Equilibrium and Stability,” Phys. Plasmas 10 (December 2003) presented at the Nineteenth IAEA Fusion 4771-4775; Princeton Plasma Physics Energy Conference (14-19 October 2002, Laboratory Report PPPL-3855 (August Lyon, France). 2003) 15 pp.

*Beidler, C.D., Kasilov, S.V., Kernbichler, *Bell, A.C., Gentile, C.A., Lasser, R.L.K., W., Maaßberg, H., Mikkelsen, D.R., and Coad, J.P., “Tritium Inventory Murakami, S., Nemov, V.V., Schmidt, Control — The Experience with DT M., Spong, D.A., Tribaldos, V., Wakasa, Tokamaks and Its Relevance for Future A., and White, R.B., “Neoclassical Trans- Machines,” Fusion Eng. Des. 66-68 port in Stellarators — Results from an (September 2003) 91-102. International Collaboration,” in the Proceedings of the 30th European Physical Belova, E.V., Davidson, R.C., Ji, H., Society Conference on Controlled Fusion and Yamada, M., “Kinetic Effects on and Plasma Physics (7-11 July 2003, the Stability Properties of Field-reversed St. Petersburg, Russia), Europhysics Conﬁ gurations: I. Linear Stability,” Phys. Con ference Abstracts 27A (European Plasmas 10 (June 2003) 2361-2371; Physical Society, 2003) paper P-3.2. Princeton Plasma Physics Laboratory Re- This conference proceedings is published port PPPL-3773 (January 2003) 46 pp. on CD-ROM. Papers available in PDF format at http://eps2003.ioffe.ru/ (as of Belova, E.V., Davidson, R.C., Ji, H., 12 November 2003). and Yamada, M., “Nonlinear and Non- ideal Effects on FRC Stability,” Princeton *Beiersdorfer, P., Bitter, M., May, M.J., Plasma Physics Laboratory Report PPPL- and Roquemore, L., “High-resolution 3759 (October 2002) 6 pp. Presented Soft X-ray Spectrometer for the NSTX at the 2002 U.S.-Japan Workshop New Tokamak,” Rev. Sci. Instrum. 74 (March Directions in Controlling and Sustaining 2003) 1974-1976. Presented at the Four- Compact Toroids (9-11 September 2002, teenth APS Topical Conference on High Osaka, Japan). Temperature Plasma Diagnostics (8-10 July 2002, Madison, Wisconsin). Belova, E.V., Gorelenkov, N.N., and Cheng, C.Z., “Self-consistent Equi lib- *Bekris, N., Skinner, C.H., Berndt, U., rium Model of Low Aspect-ratio Toroidal Gentile, C.A., Glugla, M., Schweigel, B., Plasma with Energetic Beam Ions,” Phys. “Tritium Depth Proﬁ les in 2D and 4D Plasmas 10 (August 2003) 3240-3251; CFC Tiles from JET and TFTR,” J. Nucl. Princeton Plasma Physics Laboratory Mater. 313-316 (March 2003) 501- Report PPPL-3802 (March 2003) 49 pp.

164 Belova, E.V., Gorelenkov, N.N., Cheng, Plasma Physics Laboratory Report PPPL- C.Z., and Fredrickson, E.D., “Numerical 3862 (August 2003) 6 pp. Study of Instabilities Driven by Energetic Neutral Beam Ions in NSXT,” in the §Bitter, M., Gu, M.F., Vainshtein, L.A., Proceedings of the 30th European Physical Beiersdorfer, P., Bertschinger, G., Mar- Society Conference on Controlled Fusion chuk, O., Bell, R., LeBlanc, B., Hill, and Plasma Physics (7-11 July 2003, K.W., Johnson, D., and Roquemore St. Petersburg, Russia), Europhysics L., “New Benchmarks from Tokamak Con ference Abstracts 27A (European Experiments for Theoretical Calculations Physical Society, 2003) paper P-3.102. of the Dielectronic Satellite Spectra of This conference proceedings is published Helium-like Ions,” Phys. Rev. Lett. 91 (31 on CD-ROM. Papers available in PDF December 2003) 265001/1-4; Princeton format at http://eps2003.ioffe.ru/ (as of Plasma Physics Laboratory Report PPPL- 12 November 2003). Princeton Plasma 3860 (August 2003) 13 pp. Physics Laboratory Report PPPL-3832 (July 2003) 6 pp. Bitter, M., Hill, K., Roquemore, L., Beiersdorfer, P., Thorn, D., and Gu, Ming Bernabei, S., Hosea, J., Kung, C., Feng, “Results from the NSTX X-ray Loesser, D., Rushinski, J., Wilson, J.R., Crystal Spectrometer,” Rev. Sci. Instrum. and Parker, R., “Design of a Compact 74 (March 2003) 1977-1981; Princeton Lower Hybrid Coupler for Alcator C- Plasma Physics Laboratory Report PPPL- mod,” Fusion Sci. Technol. 43 (March 3766 (January 2003) 19 pp. Presented at 2003) 145-152; Princeton Plasma Phys- the Fourteenth APS Topical Conference on ics Laboratory Report PPPL-3638 (De- High Temperature Plasma Diagnostics (8- cember 2001) 14 pp (title: A Third 10 July 2002, Madison, Wisconsin). Generation Lower Hybrid Coupler). *Blagojevic, B., Stutman, D., Finkenthal, †Biewer, T.M., Bell, R.E., Dar- M., Moos, H.W., Kaita, R., and Majeski, row, D.S., Phillips, C.K., and R., “Imaging Transmission Grating Wilson, J.R., “Observations of Aniso- Spectrometer for Magnetic Fusion Exper- tropic Ion Temperature during RF Heat- iments,” Rev. Sci. Instrum. 74 (March ing in the NSTX Edge,” AIP Conference 2003) 1988-1992. Presented at the Proceedings 694 (15 December 2003) Fourteenth APS Topical Conference on 193-196; Princeton Plasma Physics High Temperature Plasma Diagnostics (8- Laboratory Report PPPL-3813 (May 10 July 2002, Madison, Wisconsin). 2003) 4 pp. Presented at the 15th AIP Topical Conference on Radio Frequency *Bourdelle, C., Dorland, W., Garbet, Power in Plasmas (19-21 May 2003, X., Hammett, G.W., Kotschenreuther, Grand Teton National Park, Moran, M., Rewoldt, G., Synakowski, E.J., Wyoming). “Stabilizing Impact of High Gradient of Beta on Microturbulence,” Phys. Plasmas §Biewer, T.M., Bell, R.E., Feder, R., 10 (July 2003) 2881-2887. Johnson, D.W., and Palladino, R.W., “An Edge Rotation and Temperature Breslau, J., Chen, J., Fu, G., Held, E., Diagnostic on NSTX,” Rev. Sci. Instrum. Jardin, S., Kruger, S., Park, W., Parker, 75 (March 2004) 650-654; Princeton S., Samtaney, R., Schnack, D., Sovinec,

165 C., Sugiyama, L., and Strauss, H., Houlberg, W., Luce, T.C., Makowski, “Nonlinear Plasma Simulation Studies of M.A., Mikkelsen, D., Murakami, M., Tokamaks, STs, and Stellarators,” in the Prentice, R., Staebler, G., Stratton, B., Proceedings of the 30th European Physical Wade, M., West, W.P., and contributors Society Conference on Controlled Fusion to the EFDA-JET and DIII-D Work and Plasma Physics (7-11 July 2003, Programs, “Microturbulence, Heat, and St. Petersburg, Russia), Europhysics Particle Fluxes in JET and DIII-D ITB Conference Abstracts 27A (European Plasmas with Highly Reversed Magnetic Physical Society, 2003) paper P-2.103. Shear,” in the Proceedings of the 30th This conference proceedings is published European Physical Society Conference on on CD-ROM. Papers available in PDF Controlled Fusion and Plasma Physics (7- format at http://eps2003.ioffe.ru/ (as of 11 July 2003, St. Petersburg, Russia), 12 November 2003). Europhysics Conference Abstracts 27A (European Physical Society, 2003) paper Breslau, J.A. and Jardin, S.C., “A O-3.4A. This conference proceedings is Parallel Algorithm for Global Magnetic published on CD-ROM. Papers available Reconnection Studies,” Comput. Phys. in PDF format at http://eps2003.ioffe. Commun. 151 (1 March 2003) 8-24. ru/ (as of 12 November 2003). Princeton Plasma Physics Laboratory Report PPPL- Breslau, J.A. and Jardin, S.C., “Global 3841 (July 2003) 4 pp. Extended MHD Studies of Fast Magnetic Reconnection,” Phys. Plasmas 10 (May *Bush, C.E., Bell, M.G., Bell, R.E., 2003) 1291-1298; Princeton Plasma Boedo, J., Fredrickson, E.D., Kaye, Physics Laboratory Report PPPL-3751 S.M., Kubota, S., LeBlanc, B.P., Maingi, (September 2002) 16 pp. R., Maqueda, R.J., Sabbagh, S.A., Soukhanovskii, V.A., Stutman, D., Breslau, J.A., Jardin, S.C., and Park, Swain, D.W., Wilgen, J.B., Zweben, W., “Simulation Studies of the Role S.J., Davis, W.M., Gates, D.A., Johnson, of Reconnection in the ‘Current Hole’ D.W., Kaita, R., Kugel, H.W., Lee, K.C., Experiments in the Joint European Mastrovito, D., Medley, S., Menard, J.E., Torus,” Phys. Plasmas 10 (May 2003) Mueller, D., Ono, M., Paoletti, F., Park, 1665-1669; Princeton Plasma Physics H., Paul, S.J., Peng, Y-K.M., Raman, R., Laboratory Report PPPL-3770 (January Roney, P.G., Roquemore, A.L., Skinner, 2003) 10 pp. C.H., Synakowski, E.J., Taylor, G., for the NSTX team, “Conﬁ guration and Budny, R.V., “Fusion Alpha Parameters Heating Power Dependence of Edge in Tokamaks with High DT Fusion Parameters and H-mode Dynamics in Rates,” Nucl. Fusion 42 (December National Spherical Torus Experiment 2002) 1383-1393; Princeton Plasma (NSTX),” Phys. Plasmas 10 (May 2003) Physics Laboratory Report PPPL-3674 1755-1764. (February 2002) 25 pp. *Cecil, F.E., Aakhus-Witt, A., Hawbaker, Budny, R.V., Andre, R., Challis, C.D., J., Sayers, J., Bozek, A., Heidbrink, Dorland, W., Dux, R., Ernst, D.R., W.W., Darrow, D.S., Debey, T.M., Giroud, C., Gowers, C.W., Greenﬁ eld, and Marmar, E., “Thin Foil Faraday C.M., Hawkes, N., Hammett, G., Collectors as a Radiation Hard Fast Lost-

166 ion Diagnostic,” Rev. Sci. Instrum. 74 075004/1-4; Princeton Plasma Physics (March 2003) 1747-1749. Presented at Laboratory PPPL-3847 (July 2003) 9 pp. the Fourteenth APS Topical Conference on High Temperature Plasma Diagnostics (8- §Cheng, C.Z., Ren, Y., Choe, G.S., and 10 July 2002, Madison, Wisconsin). Moon, Y.-J., “Flux Rope Acceleration and Enhanced Magnetic Reconnection *Celata, C.M., Bieniosek, F.M., Hen- Rate,” Astrophys. J. Lett. 596 (20 Oct- estroza, E., Kwan, J.W., Lee, E.P., Logan, ober 2003) 1341-1346; Princeton Plasma G., Prost, L., Seidl, P.A., Vay, J.-L., Physics Laboratory PPPL-3799 (March Waldron, W.L., Yu, S.S., Barnard, J.J., 2003) 19 pp. Callahan, D.A., Cohen, R.H., Friedman, A., Grote, D.P., Lund, S.M., Molvik, A., *Chu, M.S., LaHaye, R.J., Austin, M.E. Sharp, W.M., Westenskow, G., David- Lao, L.L., Lazarus, E.A., Pletzer, A., son, R.C., Efthimion, P., Gilson, E., Ren, C., Strait, E.J., Taylor, T.S., and Grisham, L.R., Kaganovich, I., Qin, Waelbroeck, F.L., “Study of a Low Beta Hong, Startsev, E.A., Bernal, S., Cul, Y., Classical Tearing Mode in DIII-D,” Feldman, D., Godlove, T.F., Harber, I., Phys. Plasmas 9 (November 2002) 4584- Harris, J., Kishek, R.A., Li, H., O’Shea, 4590. P.G., Quinn, B., Reiser, M., Valfells, A., Walter, M., Zou, Y., Rose, D.V., and Chu, T.K., “On the Node in the Current Welch, D.R., “Progress in Heavy Ion Density Proﬁ le during Current Peaking Fusion Research,” Phys. Plasmas 10 (May in a Sawtooth Oscillation,” Phys. Plasmas 2003) 2064-2070. 9 (October 2002) 4383-4384.

Chance, M.S., Chu, M.S., Glasser, A.H., Clark, Daniel S. and Fisch, Nathaniel J., Okabayashi, M., Perkins, F.W., Garofalo, “Operating Regime for a Backward Ra- A., Navratil, G., Jackson, G., LaHaye, R., man Laser Amplifi er in Preformed Plas- Reimerdes, H., Scoville, T., Strait, E., and ma,” Phys. Plasmas 10 (August 2003) Edgell, D., “Modeling of the Feedback 3363-3370; Princeton Plasma Physics Stabilization of the Resistive Wall Mode Laboratory Report PPPL-3780 (February in Tokamaks,” in the Proceedings of the 2003) 9 pp. 30th European Physical Society Conference on Controlled Fusion and Plasma Physics §Clark, Daniel S. and Fisch, Nathaniel (7-11 July 2003, St. Petersburg, Russia), J., “Simulations of Raman Laser Ampli- Europhysics Conference Abstracts 27A fi cation in Ionizing Plasmas,” Phys. (European Physical Society, 2003) paper Plasmas 10 (December 2003) 4837-4847; P-2.109. This conference proceedings is Princeton Plasma Physics Laboratory published on CD-ROM. Papers available Report PPPL-3829 (June 2003) 12 pp in PDF format at http://eps2003.ioffe. (title: Particle-in-cell Simulations of ru/ (as of 12 November 2003). Raman Laser Amplifi cation in Ionizing Plasmas). *§Chen, Liu; White, Roscoe B.; and Zonca, F., “Zonal Flow Dynamics and §Clark, Daniel S., and Fisch, Nathaniel Size-scaling of Anomalous Transport,” J., “Particle-in-cell Simulations of Ra- Phys. Rev. Lett. 92 (20 February 2004) man Laser Amplifi cation in Preformed

167 Plasmas,” Phys. Plasmas 10 (December Cecil, F.E., Egedal, J., Goloborod’ko, 2003) 4848-4855; Princeton Plasma V.Ya., Gorelenkov, N.N., Isobe, M., Physics Laboratory Report PPPL-3830 Kaye, S., Miah, M., Paoletti, F., Redi, (June 2003) 8 pp. M.H., Reznik, S.N., Rosenberg, A., White, R., Wyatt, D., and Yavorskij, V.A., Cohen, S.A., Siefert, N.S., Stange, S., “Measurements of Prompt and MHD- Boivin, R.F., Scime, E.E., and Levinton, induced Fast Ion Loss from National F.M., “Ion Acceleration in Plasmas Spherical Torus Experiment Plasmas” Emerging from a Helicon-heated Mag- Princeton Plasma Physics Laboratory ne tic-mirror Device,” Phys. Plasmas Report PPPL-3754 (October 2002) 5 pp. 10 (June 2003) 2593-2598; Princeton Presented at the Nineteenth IAEA Fusion Plasma Physics Laboratory Report PPPL- Energy Conference (14-19 October 2002, 3793 (March 2003) 10 pp Lyon, France).

*Cooper, W.A., Ferrando, I., Margalet, Davidson, R.C., “Frontiers in High S., Allfrey, S.J., Isaev, M.Yu., Mikhailov, Energy Density Physics: The X-Games of M.I., Shafranov, V.D., Subbotin, A.A., Contemporary Science,” Committee on Narushima, Y., Okamura, S., Suzuki, High Energy Density Plasma Physics C., Yamazaki, K., Fu, G.Y. Ku, L.P., (R.C. Davidson, Chair) Plasma Science Monticello, D.A., Redi, M.H., Reiman, Committee/Board on Physics and As- A.H., Zarnstorff, M.C., Nuhrenberg, tronomy Division on Engineering and J., and Todd, T.N., “Bootstrap Cur rent Physical Science/Nation Research Coun- Destabilization of Ideal MHD Modes cil of the National Academies (National in Three-dimensional Reactor Con- Academies Press, Washington, DC, ﬁ gurations,” Plasma Phys. Control. Fu- 2003). sion 44 (December 2002) B357-373. Presented at the 29th European Physical Davidson, R.C., Kaganovich, I.D., Lee, Society on Plasma Physics and Controlled W.W., Qin, H., Startsev, E.A., Tzenov, S., Fusion (17-21 June 2002, Montreux, Friedman, A., Barnard, J.J., Cohen, R.H., Switzerland). Grote, D.P., Lund, S.M., Sharp, W.M., Celata, C.M., de Hoon, M., Henestroza, *Cortes, S.R., Hawkes, N.C. Lotte, P., E., Lee, E.P., Yu, S.S., Vay, J.-L., Welch, Fenzi, C., Stratton, B.C., Hobirk, J., D.R., Rose, D.V., and Olson, C. L., DeAngelis, R., Orsitto, F., and Varandas, “Overview of Theory and Modeling in C.A.F., “Measurement of the Plasma Ra- the Heavy Ion Fusion Virtual National dial Electric Field by the Motional Stark Laboratory,” Laser and Particle Beams 20 Effect diagnostic on JET Plasmas,” Rev. (July 2002) 377-384; Princeton Plasma Sci. Instrum. 74 (March 2003) 1596- Physics Laboratory Report PPPL-3804 1600. Presented at the Fourteenth APS (April 2003) 18 pp. Topical Conference on High Temperature Plasma Diagnostics (8-10 July 2002, Davidson, Ronald C., Qin, Hong, and Madison, Wisconsin). Lund, Steven, M., “Truncated Thermal Equilibrium Distribution for Intense Darrow, D.S., Medley, S.S., Roquemore, Beam Propagation,” Phys. Rev. ST Accel. A.L., Heidbrink, W.W., Alekseyev, A., Beams 6 (February 2003) Article No.

168 024402 (8 pages); Princeton Plasma Dodin, I.Y. and Fisch, N.J., “Relativistic Physics Laboratory Report PPPL-3790 Electron Acceleration in Focused Laser (February 2003) 16 pp. Fields after Above-threshold Ionization,” Phys. Rev. E 68 (18 November 2003) Davidson, Ronald C.; Qin, Hong; and 056402/1-8; Princeton Plasma Physics Shvets, Gennady, “Wall-impedance- Laboratory Report PPPL-3805 (April driven Collective Instability in Intense 2003) 12 pp (title: GeV Electrons Ac- Charged Particle Beams,” Phys. Rev. ST celeration in Focused Laser Fields after Accel. Beams 6 (October 2003) Article Above-threshold Ionization). No. 104402 (12 pages). Dodin, I.Y., Fisch, N.J., and Fraiman, Davidson, Ronald C.; Qin, Hong; G.M., “Drift Lagrangian for Relativistic Tzenov, Stephan I.; and Startsev, Edward Particle in Intense Laser Field,” JETP A., “Kinetic Description of Intense Beam Lett. 78 (2003) 202; Princeton Plasma Propagation Through a Periodic Focusing Physics Laboratory Report PPPL-3778 Field for Uniform Phase-space Density,” (February 2003) 5 pp with the title: Phys. Rev. ST Accel. Beams 5 (August “Lagrangian Formulation of Relativistic 2002) Article No. 084402 (16 pages); Particle Average Motion in a Laser Field Princeton Plasma Physics Laboratory Re- of Arbitrary Intensity.” port PPPL-3789 (February 2003) 35 pp. *Dodin, I.Y., Fraiman, G.M., Malkin, Davis, W. and Mastrovito, D., “DbAccess: V.M., and Fisch, N.J., “Ampliﬁ cation Interactive Statistics and Graphics for of Short Laser Pulses by Raman Back- Plasma Physics Databases,” Princeton scattering in Capillary Plasmas,” J. Exp. Plasma Physics Laboratory Report PPPL- Theor. Phys. (Russian) 95 (October 3880 (October 2003) 6 pp. Presented the 2002) 625-638 [Russian citation: Zh. 4th IAEA Technical Committee Meeting Eksp. Teor. Fiz. 122 (October 2002) on Control, Data Acquisition, and Remote 723-737]. Participation for Fusion Research (21- 23 July 2003, San Diego, California); Dorf, L., Raitses, Y., and Fisch, N.J., proceedings to be published by Fusion “Diagnostic Setup for Characterization of Engineering and Design. Near-anode Processes in Hall Thrusters,” Princeton Plasma Physics Laboratory *Deng, B.H., Chen, H.C., Domier, Report PPPL-3817 (May 2003) 4 pp. C.W., Johnson, M., Lee, K.C., Luhmann, Presented at the 28th International Electric N.C., Jr., Nathan, B.R., and Park, H., Propulsion Conference (IEPC 2003) (17- “Development of a Multichannel Far- 21 March 2003, Toulouse, France). Pro- infrared Tangential Interferometer/Polar- ceedings published on CD-ROM. imeter for the National Spherical Torus Experiment,” Rev. Sci. Instrum. 74 Dorf, L., Raitses Y., and Fisch, N.J., (March 2003) 1617-1620. Presented at “Diagnostic Setup for Characterization of the Fourteenth APS Topical Conference on Near-anode Processes in Hall Thrusters,” High Temperature Plasma Diagnostics (8- Princeton Plasma Physics Laboratory 10 July 2002, Madison, Wisconsin). Report PPPL-3864 (September 2003) 17

169 pp; to be published in the May 2004 issue Magnetic Fields,” J. Appl. Phys. 93 (15 of Review of Scientiﬁ c Instruments with March 2003) 3481-3485; Princeton Plas- the title “Electrostatic Probe Apparatus ma Physics Laboratory Report PPPL- for Measurements in the Near-anode 3731 (July 2002) 12 pp. Region of Hall Thrusters.” Dunaevsky, A., Raitses, Y., and Fisch, *Drevlak, M., Heyn, M.F., Kalyuzhnvyj, N.J., “Secondary Electron Emission from V.N., Kasilov, S.V., Kernbichler, W., Dielectric Materials of a Hall Thruster Monticello, D., Nemov, V.V., Nührenberg, with Segmented Electrodes,” Phys. Plas- J., and Reiman, A., “Effective Ripple for mas 10 (June 2003) 2574-2577; Prince- the W7-X Magnetic Field Calculated by ton Plasma Physics Laboratory Report the PIES Code,” in the Proceedings of the PPPL-3787 (February 2003) 16 pp. 30th European Physical Society Conference on Controlled Fusion and Plasma Physics Dunaevsky, A., Raitses, Y., and Fisch, N.J., (7-11 July 2003, St. Petersburg, Russia), “Yield of Secondary electron Emission Europhysics Conference Abstracts 27A from Ceramic Materials of Hall Thruster (European Physical Society, 2003) paper with Segmented Electrodes,” presented at P-1.12. This conference proceedings is the 28th International Electric Propulsion published on CD-ROM. Papers available Conference (IEPC 2003) (17-21 March in PDF format at http://eps2003.ioffe. 2003, Toulouse, France). Proceedings ru/ (as of 12 November 2003). published on CD-ROM.

*Drevlak, M., Heyn, M.F., Kasilov, S.V., Efthimion, P.C., Davidson, R.C., Gilson, Kernbichler, W., Monticello, D., Nemov, E.P., Grisham, L.R., Yu, S.S., and Logan, V.V., Nührenberg, J., and Reiman, A., B.Grant, “RF Plasma Source for Heavy “Bootstrap Current for Neoclassically Ion Beam Charge Neutralization,” in the Optimized Stellarator Systems,” in the Proceedings of the 2003 Particle Accelerator Proceedings of the 30th European Physical Conference (PAC2003) 4 (12-16 May Society Conference on Controlled Fusion 2003, Portland, Oregon) 2661-2663. and Plasma Physics (7-11 July 2003, St. Petersburg, Russia), Europhysics Efthimion, Philip C.; Gilson, Erik; Conference Abstracts 27A (European Grisham, Larry; Kolchin, Pavel; Davidson, Physical Society, 2003) paper P-4.15. Ronald C.; Yu, Simon; and Logan, B. This conference proceedings is published Grant, “ECR Plasma Source for Heavy on CD-ROM. Papers available in PDF Ion Beam Charge Neutralization,” Laser format at http://eps2003.ioffe.ru/ (as of and Particle Beams 21 (January 2003) 12 November 2003). 37-40.

Dunaevsky, A. and Fisch, N.J., “Measuring Efthimion, P.C., Taylor, G., Jones, B., the Plasma Density of a Ferroelectric Munsat, T., Hosea, J.C., Kaita, R., Plasma Source in an Expanding Plasma,” Majeski, R., Spaleta, J., Wilson, J.R., J. Appl. Phys. 95 (May 2004) 4621- Rasmussen, D.A., Wilgen, J., Bell, G., 4626. Ram, A.K., Bers, A., Decker, J., Harvey, R.W., Smirnov, A.P., Lashmore-Davies, Dunaevsky, A., Raitses, Y., and Fisch, N.J., C.N., “Application of Electron Bernstein “Ferroelectric Cathodes in Transverse Wave Heating and Current Drive to High

170 β Plasmas,” presented at the Nineteenth Fredrickson, E.D., Cheng, C.Z., Darrow, IAEA Fusion Energy Conference (14-19 D., Fu, G., Gorelenkov, N.N., Kramer, October 2002, Lyon, France). G., Medley, S.S., Menard, J., Roquemore, L., Stutman, D., and White, R.B., “Wave *Egedal, J., Redi, M.H., Darrow, D.S., Driven Fast Ion Loss in the National and Kaye, S.M., “Efﬁ cient Evaluation Spherical Torus Experiment,” Phys. of Beam Ion Conﬁ nement in Spherical Plasmas 10 (July 2003) 2852-2862; Tokamaks,” Phys. Plasmas 10 (June Princeton Plasma Physics Laboratory Re- 2003) 2372-2381. port PPPL-3774 (January 2003) 31 pp.

Ethier, S. and Lin, Z., “Porting the 3D Fredrickson, E.D., Cheng, C.Z., Darrow, Gyrokinetic Particle-in-cell Code GTC to D., Fu, G., Gorelenkov, N.N., Kramer, the CRAY/NEC SX-6 Vector Architecture: G., Medley, S.S., Menard, J., Roquemore, Perspectives and Challenges,” Plasma L., Stutman, D., and White, R.B., “Wave Physics Laboratory Report PPPL-3869 Driven Fast Ion Loss in the National (September 2003) 4 pp. Presented at Spherical Torus Experiment,” in the the 18th International Conference on Proceedings of the 30th European Physical Numerical Simulation of Plasmas (ICNSP Society Conference on Controlled Fusion ’03) (7-10 September 2003, Cape Cod, and Plasma Physics (7-11 July 2003, Massachusetts). St. Petersburg, Russia), Europhysics Conference Abstracts 27A (European *Federici, G. and Skinner, C.H., “Tri- Physical Society, 2003) paper P-3.99. tium Inventory in the Materials of the This conference proceedings is published ITER Plasma Facing Components,” on CD-ROM. Papers available in PDF in the Proceedings of the IAEA Technical format at http://eps2003.ioffe.ru/ (as of Meeting on Atomic and Plasma-Material 12 November 2003). Princeton Plasma Interaction Data for Fusion Science and Physics Laboratory Report PPPL-3851 Technology (28-31 October 2002, FZ (August 2003) 4 pp. Jülich, Germany). Springer Publishing Company (Heidelberg) Series on Atoms Fredrickson, E.D., White, Roscoe, and and Plasmas Editors R. Clark (IAEA) and Chen, Liu, “Bounce Precession Fishbones D. Reiter (FZJ) (summer 2003). in the National Spherical Tokamak Experiment,” Nucl. Fusion 43 (October Fisch, N.J. and Malkin, V.M., “Gen- 2003) 1258-1264; Princeton Plasma eration of Ultrahigh Intensity Laser Physics Laboratory Report PPPL-3715 Pulses,” Phys. Plasmas 10 (May 2003) (June 2002) 12 pp. 2056-2063; Princeton Plasma Physics Laboratory Report PPPL-3821 (June *Fujita, T., Aniel, T., Barbato, E., Behn, 2003) 10 pp. R., Bell, R.E., Field, A.R., Fukuda, T., Gohil, P., Ida, K., Imbeaux, F., Kirneva, §Fisch, N.J., Rax, J.M., and Dodin, N.A., Laborde, L., Litaudon, X., Mazon, I.Y., “Current Drive in a Ponderomotive D., Peng, Y-K.M., Razumova, K.A., Rice, Potential with Sign Reversal,” Phys. Rev. J.E., Sakamoto, Y., Sips, A.C.C., Suzuki, Lett. 91 (14 November 2003) 205004/1- T., Takenaga, H., the ITPA Topical 4; Princeton Plasma Physics Laboratory Group on Transport and ITB Physics, Report PPPL-3846 (July 2003) 5 pp. and the International ITB Database

171 Working Group, “Key Quantities for L.P., LaMarche, P.H., Myers, M.C., ITB Formation and Sustainment,” in the Park er, J.J., Parsells, R.F., Payen, M., Proceedings of the 30th European Physical Raftopoulos, S., and Sethian, J.K., “De- Society Conference on Controlled Fusion velopment of a Silicon Based Electron and Plasma Physics (7-11 July 2003, Beam Transmission Window for use in St. Petersburg, Russia), Europhysics a KrF Excimer Laser System,” Fusion Conference Abstracts 27A (European Sci. Technol. 43 (May 2003) 414-419; Physical Society, 2003) paper P-2.131. Prince ton Plasma Physics Laboratory This conference proceedings is published Report PPPL-3760 (November 2002) on CD-ROM. Papers available in PDF 20 pp. Presented at the Second IAEA format at http://eps2003.ioffe.ru/ (as of Tech nical Committee Meeting on Physics 12 November 2003). and Technology of Inertial Fusion Energy Targets and Chambers (17-19 June 2002, *Gao, Qingdi; Li, Fangzhu; Zhang, San Diego, California). Jinhua; and Budny, R.V., “Establishment of Transport Barriers by Proﬁ le Control Gilson, E., Davidson, R.C., Efthimion, in HL-2A+,” in the Proceedings of the P., Majeski R., and Qin, H., “Paul Trap 30th European Physical Society Conference Simulator Experiment,” Laser and Par tion Controlled Fusion and Plasma Physics cle Beams 21 (October 2003) 549-552. (7-11 July 2003, St. Petersburg, Russia), Europhysics Conference Abstracts 27A Gilson, E.P., Davidson, R.C., Efthimion, (European Physical Society, 2003) paper P.C., Majeski R., and Qin, H., “Recent P-1.149. This conference proceedings is Results from the Paul Trap Simulator,” published on CD-ROM. Papers available in the Proceedings of the 2003 Particle in PDF format at http://eps2003.ioffe. Accelerator Conference (PAC2003) 4 (12- ru/ (as of 12 November 2003). 16 May 2003, Portland, Oregon) 2655- 2657. *Garbet, X., Baranov, Y., Bateman, G., Benkadda, S., Beyer, P., Budny, R., et al., †Gilson, E.P., Davidson, R.C., Efthi- “Micro-stability and Transport Modelling mion, P.C., Majeski R., Qin, H., and of Internal Transport Barriers in JET,” Startsev, E.A., “Modeling Intense Beam presented at the Nineteenth IAEA Fusion Propagation in the Paul Trap Simulator Energy Conference (14-19 October 2002, Experiment (PTSX),” AIP Conference Lyon, France). Proceedings 692 (2 December 2003) 211-220. Presented at the 2003 Workshop Gates, D.A., for the NSTX Research on Non-neutral Plasmas (7-11 July 2003, Team, “High Beta, Long Pulse, Bootstrap Santa Fe, New Mexico). Sustained Scenarios on the National Spherical Torus Experiment (NSTX),” Gorelenkov, N.N., Berk, H.L., Budny, Phys. Plasmas 10 (May 2003) 1659-1664; R., Cheng, C.Z., Fu, G.-Y., Heidbrink, Princeton Plasma Physics Laboratory Re- W.W., Kramer, G.J., Meade, D., and port PPPL-3791 (February 2003) 31 pp. Nazikian, R., “Study of Thermonuclear Alfvén Instabilities in Next Step Burning Gentile, C.A., Fan, H.M., Hartﬁ eld, Plasma Proposals,” Nucl. Fusion 43 (July J.W., Hawryluk, R.J., Hegeler, F., 2003) 594-605. Heit zenroeder, P.J., Jun, C.H., Ku,

172 Gorelenkov, N.N., Fredrickson, E., (7-11 July 2003, St. Petersburg, Russia), Belova, E., Cheng, C.Z., Gates, D., and Europhysics Conference Abstracts 27A White R., “Sub-cyclotron Instability of (European Physical Society, 2003) paper Alfvén Eigenmodes due to Energetic Ions P-2.100. This conference proceedings is in Low Aspect Ratio Plasmas,” in the published on CD-ROM. Papers available Proceedings of the 30th European Physical in PDF format at http://eps2003.ioffe. Society Conference on Controlled Fusion ru/ (as of 12 November 2003). Princeton and Plasma Physics (7-11 July 2003, Plasma Physics Laboratory Report PPPL- St. Petersburg, Russia), Europhysics 3858 (August 2003) 4 pp. Conference Abstracts 27A (European Physical Society, 2003) paper P-3.103. Gorelenkov, N.N., Zakharov, L.E., and This conference proceedings is published Gorelenkova, M.V., “Toroidal Plas ma on CD-ROM. Papers available in PDF Thruster for Interplanetary and Inter- format at http://eps2003.ioffe.ru/ (as of stellar Space Flights,” AIAA Journal 42 12 November 2003). Princeton Plasma (May 2003) 774-784; Princeton Plasma Physics Laboratory Report PPPL-3857 Physics Laboratory PPPL-3592 (July (August 2003) 4 pp. 2001) 30 pp.

Gorelenkov, N.N., Fredrickson, E., *Graves, J.P., Sauter, O., Gorelenkov, Belova, E., Cheng, C.Z., Gates, D., N.N., “The Internal Kink Mode in an Kaye, S., and White, R., “Theory and Anisotropic Flowing Plasma with Ap- Observations of High Frequency Alfvén plication to Modeling Neutral Beam In- Eigenmodes in Low Aspect Ratio Plasma,” jected Sawtoothing Discharges,” Phys. Nucl. Fusion 43 (April 2003) 228-233; Plasmas 10 (April 2003) 1034-1047. Princeton Plasma Physics Laboratory Report PPPL-3828 (June 2003) 17 pp. *Greenﬁ eld, C.M., Ferron, J.R., Murakami, M. Wade, M.R., Budny, R.V., Gorelenkov, N.N., Gondhalekar, A., Burrell, K.H., Casper, T.A., DeBoo, J.C., Korotkov, A.A., Sharapov, S.E., Testa, Doyle, E.J., Garofalo, A.M., Jayakumar, D., and Contributors to the EFDA-JET R.J., Kessel, C., Lao, L.L., Lohr. J., Luce, Workprogramme, “Mechanism of Radial T.C., Makowski, M.A., Menard, J.E., Redistribution of Energetic Trapped Ions Petrie, T.W., Petty, C.C., Pinsker, R.I., Due to m=2/n=1 Internal Reconnection Prater, R., Politzer, P.A., St. John, H.E., in Joint European Torus Shear Optimized Taylor, T.S., West, W.P., and the DIII-D Plasmas,” Phys. of Plasmas 10 (March National Team, “Progress Toward Fully 2003) 713-725; Princeton Plasma Physics Noninductive, High Beta Discharges in Laboratory Report PPPL-3653 (January DIII-D,” in the Proceedings of the 30th 2002) 31 pp. European Physical Society Conference on Controlled Fusion and Plasma Physics (7- Gorelenkov, N.N., Mantsinen, M.J., 11 July 2003, St. Petersburg, Russia), Sharapov, S.E., Cheng, C.Z., and the Europhysics Conference Abstracts 27A JET-EFDA Contributors, “Modeling of (European Physical Society, 2003) paper ICRH H-minority-driven n=1 Resonant P4.92. This conference proceedings is Modes in JET,” in the Proceedings of the published on CD-ROM. Papers available 30th European Physical Society Conference in PDF format at http://eps2003.ioffe. on Controlled Fusion and Plasma Physics ru/ (as of 12 November 2003).

173 Grisham, L.R., “Potential Roles for *Heidbrink, W.W., Fredrickson, E., Heavy Negative Ions as Driver Beams” to Gorelenkov, N.N., Hyatt, A.W., Kramer, appear in GSI Plasma Physics Scientifi c G., and Luo, Y., “An Alfvén Eigenmode Report “High Energy Density in Mat- Similarity Experiment,” Plasma Phys. ter,” Chapter 4 (2003), and in Laser Control. Fusion 45 (June 2003) 983- and Particle Beams 21 (October 2003) 997. 545-548, proceedings of the Heavy Ion Fusion Conference (May 2002, Moscow, *Heidbrink, W.W., Miah, M., Darrow, D., Russia). LeBlanc, B., Medley, S.S., Roquemore, A.L., and Cecil, F.E., “The Confi nement Grisham, Larry R., “Evaluation of of Dilute Populations of Beam Ions in the Negative-Ion-Beam Driver Concepts for National Spherical Torus Experiment,” Heavy Ion Fusion,” Fusion Sci. Techn. Nucl. Fusion 43 (August 2003) 883- 43 (March 2003) 191-199; Princeton 888. Plasma Physics Laboratory Report PPPL- 3643 (January 2002) 18 pp. *Hender, T.C., Sauter, O., Alper, B., Angioni, C., de Baar, M., De Benedetti, Grisham, L.R., Hahto, S.K., Hahto, M., Belo, P., Bigi, M., Borba, D.N., S.T., Kwan, J.W., Leung, K.N., “Proof- Bolzonella, T., Budny, R., et al., “Saw- of-Concept Experiments for Negative tooth, Neo-classical Tearing Mode and Ion Driver Beams for Heavy Ion Fusion,” Error Field Studies in JET,” presented in the Proceedings of the 2003 Particle at the Nineteenth IAEA Fusion Energy Accelerator Conference (PAC2003) 5 (12- Con ference (14-19 October 2002, Lyon, 16 May 2003, Portland, Oregon) 3309- France). 3311; Princeton Plasma Physics Lab- oratory Report PPPL-3811 (May 2003) Hudson, S.R. and Hegna , C.C., 3 pp. “Marginal Stability Boundaries for Infi nite-n Ballooning Modes in a Quasi- *Hahto, S.K., Hahto, S.T., Kwan, axisymmetric Stellarator,” Phys. Plasmas J.W., Leung, K.N., and Grisham, L.R., 10 (December 2003) 4716-4727; Prince- “Negative Chlorine Ions from Multicusp ton Plasma Physics Laboratory Report Ratio Frequency Ion Source for Heavy PPPL-3871 (September 2003) 31 pp. Ion Fusion Applications,” Rev. Sci. Instrum. 74 (June 2003) 2987-2991. Hudson, S.R., Monticello, D.A., Rei- man, A.H., Boozer, A.H., Strickler, §Hammett, G.W., Jardin, S.C., and D.J., Hirshman, S.P., and Zarnstorff, Stratton, B.C., “Non-existence of Normal M.C., “Eliminating Islands in High- Tokamak Equilibria with Negative Cen- pressure Free-boundary Stellarator Mag- tral Current,” Phys. Plasmas 10 (October netohydrodynamic Equilibrium Solu- 2003) 4048-4052; Princeton Plasma tions” Phys. Rev. Lett. 89 (30 December Phys ics Laboratory Report PPPL-3788 2002) 275003/1-4; Princeton Plasma (February 2003) 5 pp (title: On the Phys ics Laboratory Report PPPL-3762 Existence of Tokamak Equilibria with (November 2002) 4 pp. Negative Central Current).

174 §Hudson, S.R., Monticello, D.A., in PDF format at http://eps2003.ioffe. Reiman, A.H., Strickler, D.J., Hirsh- ru/ (as of 12 November 2003). man, S.P., Ku, L.-P., Lazarus, E., Brooks, A., Zarnstorff, M.C., Boozer, *Jaeger, E.F., Berry, L.A., Myra, J.R., A.H., Fu, G.-Y., and Neilson, G.H., Batchelor, D.B. D’Azevedo, E. Bonoli, “Constructing Integrable High-pressure P.T., Phillips, C.K., Smithe, D.N., Full-current Free-boundary Stellarator D’Ippolito, D.A., Carter, M.D., Du- Mag netohydrodynamic Equilibrium mont, R.J., Wright, J.C., and Harvey, So lu tions,” Nucl. Fusion 43 (October R.W., “Sheared Poloidal Flow Driven by 2003) 1040-1046; Princeton Plasma Mode Conversion in Tokamak Plasmas,” Phys ics Laboratory Report PPPL-3867 Phys. Rev. Lett. 90 (16 May 2003) (September 2003) 19 pp. 195001/1-4.

*Isobe, M., Darrow, D.S., Kotani, J., Jardin, S.C., Kessel, C.E., Meade, D., and Shimizu, A., Suzuki, C., Yoshimura, Y., Neumeyer, C.L., Jr., “Systems Analysis of Minami, T., Takahashi, C., Nagaoka, a Compact Next Step Burning Plasma K., Nishimura, S., Toi, K., Matsuoka, Experiment,” Fusion Sci. Technol. 43 K., Okamura, S., and the CHS Group, (March 2003) 161-175; Princeton Plasma “Energy and Pitch Angle-resolved Mea- Physics Laboratory Report PPPL-3666 surements of Escaping Helically Trapped (February 2002) 26 pp. Energetic Ions at the Small Major Radius Side of the Compact Helical System,” Jardin, S.C., Kessel, C.E., Menard, J., Rev. Sci. Instrum. 74 (March 2003) 1739- Mau, T.K., Miller, R., Najmabadi, F., 1742. Presented at the Fourteenth APS Chan, V.S., Lao, L.L., Linliu, Y.R., Topical Conference on High Temperature Miller, R.L., Petrie, T., Politzer, P.A., Plasma Diagnostics (8-10 July 2002, and Turbull, A.D., “Physics Basis for a Madison, Wisconsin). Spherical Torus Power Plant,” Fusion Eng. Des. 65 (February 2003) 165-197. *Jackson, G.L., Anderson, P.M., Bialek, J., Cary, W.P., Campbell, G.L., Garofalo, Ji, Hantao; Terry, Stephen; Yamada, A.M., Hatcher, R., Kellman, A.G., Masaaki; Kulsrud, Russell; Kuritsyn, LaHaye, R.J., Nagy, A., Navratil, G.A., Aleksey; and Ren, Yang, “Electromagnetic Okabayashi, M., Pawley, C.J., Reimerdes, Fluctuations during Fast Reconnection H., Scoville, J.T., Strait, E.J., and in a Laboratory Plasma,” Phys. Rev. Szymanski, D.D., “Initial Results from Lett. 92 (19 March 2004) 115001/1- the New Internal Magnetic Field Coils for 4; Princeton Plasma Physics Laboratory Resistive Wall Mode stabilization in the Report PPPL-3784 (February 2003) 10 DIII-D Tokamak,” in the Proceedings of the pp. To be submitted to Physical Review 30th European Physical Society Conference Letters. on Controlled Fusion and Plasma Physics (7-11 July 2003, St. Petersburg, Russia), *Jing, J., Lee, J., Spirock, T.J., Xu, Y., Europhysics Conference Abstracts 27A Wang, H., and Choe, G.S., “Periodic (European Physical Society, 2003) paper Motion Along a Solar Filament Initiated P-4.47. This conference proceedings is by a Subﬂ are,” Astrophys. J. 584 (Feb- published on CD-ROM. Papers available ruary 2003) L103-L106.

175 §Johnson, D. and the NSTX Team, Kaganovich, I.D., Davidson, R.C., and “Diagnostic Development for ST Plasmas Startsev, E.A., “Ionization Cross-sections on NSTX,” Plasma Phys. Control. 45 for Ion-atom Collisions in High Energy (November 2003) 1975-1987; Princeton Ion Beams,” in the Proceedings of the 2003 Plasma Physics Laboratory Report PPPL- Particle Accelerator Conference (PAC2003) 3822 (June 2003) 26 pp. 3 (12-16 May 2003, Portland, Oregon) 1667-1669. Johnson, D., Brown, T., Neilson, H., Schilling, G., Takahashi, H., Zarnstorff, Kaganovich, I.D., O’Rourke, S., Lee, M., Cole, M., Lazarus, E., and Fenster- Edward P., Davidson, R.C., and Startsev, macher, M., “Diagnostics Plan for the E.A., “Plasma Neutralization Models for National Compact Stellarator Exper- Intense Ion Beam Transport in Plasma,” iment,” Rev. Sci. Instrum. 74 (March in the Proceedings of the 2003 Particle 2003) 1787-1790. Presented at the Accelerator Conference (PAC2003) 5 (12- Fourteenth APS Topical Conference on 16 May 2003, Portland, Oregon) 2975- High Temperature Plasma Diagnostics (8- 2977. 10 July 2002, Madison, Wisconsin). Kaganovich, Igor D. and Polomarov, Oleg, Jones, B., Efthimion, P.C., Taylor, G., “Self-consistent System of Equations for a Munsat, T., Wilson, J.R., Hosea, J.C., Kinetic Description of the Low-pressure Kaita, R., Majeski, R., Maingi, R., Discharges Accounting for the Nonlocal Shiraiwa, S., Spaleta, J., and Ram, A.K., and Collisionless Electron Dynamics,” “Controlled Optimization of Mode Phys. Rev. E 68 (August 2003) Article Conversion from Electron Bernstein No. 026411 (11 pages); Princeton Plasma Waves to Extraordinary Mode in Mag- Physics Laboratory Report PPPL-3814 netized Plasma,” Phys. Rev. Lett. 90 (May 2003) 29 pp. (25 April 2003) 165001/1-4; Princeton Plasma Physics Laboratory Report PPPL- Kaganovich, Igor D.; Startsev, 3822 (June 2003) 26 pp. Edward A.; and Davidson, Ronald C., “Comparison of Quantum-mechanical Kaganovich, I.D., “Anomalous Capacitive and Classical Trajectory Calculations Sheath with Deep Radio-frequency Elec- of Cross Section for Ion-atom Impact tric-ﬁ eld Penetration,” Phys. Rev. Lett. Ionization of Negative and Positive Ions 89 (23 December 2002) 265006/1-4; for Heavy-ion Fusion Applications,” Princeton Plasma Physics Laboratory Phys. Rev. A 68 (August 2003) Article Report PPPL-3649 (January 2002) No. 022707 (6 pages); Princeton Plasma 17 pp. Physics Laboratory Report PPPL-3812 (May 2003) 15 pp (title: Comparison Kagavonich, Igor D., “How to Patch of Quantum Mechanical and Classical Active Plasma and Collisionless Sheath: Trajectory Calculations of Cross Section Practical Guide,” Phys. Plasmas 9 (No- for Ion-atom Impact Ionization of vember 2002) 4788-4793; Princeton Negative — and Positive — ions for Plasma Physics Laboratory Report PPPL- Heavy Ion Fusion Applications). 3741 (August 2002) 8 pp.

176 §Kaganovich, Igor D.; Startsev, Edward Energy Conference (14-19 October 2002, A.; and Davidson, Ronald C., “Scaling Lyon, France). Cross Sections for Ion-atom Impact Ionization,” Phys. Plasmas 11 (March *Kawai, M., Akino, N., Ebisawa, N., 2004) 1229-1232; Princeton Plasma Grisham, L., Hanada, M., Honda, A., Physics Laboratory Report PPPL-3819 Inoue, T., Kazawa, M., Kikuchi, K., (June 2003) 43 pp. Kuriyama, M., Kusanagi, N., Mogaki, K., Noto, K., Ohga, T., Ooshima, K., Tanai, *Kageyama, Akira; Ji, Hantao; and Y., Umeda, N., Usui, K., Yamamoto, T., Goodman, Jeremy, “Circulation in a Yamazaki, H., and Watanabe, K., “Progress Short Cylindrical Couette System,” of Negative Ion Source Improvement in Prince ton Plasma Physics Laboratory N-NBI for JT-60U,” Fus. Sci. Technol. Report PPPL-3836 (July 2003) 32 pp; 44 (September 2003) 508-512. Presented submitted to Physics of Fluids. at the 15th ANS Topical Meeting on the Technology Fusion Energy (17-21 November Kaita, R., Majeski, R., Boaz, M., 2002, Washington, DC). Efthimion, P., Jones, B., Hoffman, D., Kugel, H., Menard, J., Munsat, T., Post- §Kaye, S.M., Bush, C.E., Fredrickson, Zwicker, A., Soukhanovskii, V., Spaleta, E., LeBlanc, B., Maingi, R., and Sabbagh, J., Taylor, G., Timberlake, J., Woolley, R., S.A., “Low- to High-mode Transi tions Zakharov, L., Finkenthal, M., Stutman, in the National Spherical Torus Ex- D., Antar, G., Doerner, R., Luckhardt, periment,” Phys. Plasmas 10 (October S., Maingi, R., Maiorano, M., and Smith, 2003) 3953-3960; Princeton Plasma S., “Spherical Torus Plasma Interactions Physics Laboratory Report PPPL-3845 with Large-area Liquid Lithium Surfaces (July 2003) 27 pp. in CDX-U,” Fusion. Eng. Des. 61-62 (November 2002) 217-222; Princeton Kessel, C.E., Ferron, J.R., Greenﬁ eld, Plasma Physics Laboratory Report PPPL- C.M., Menard, J.E., and Taylor T.S., 3648 (January 2002) 12 pp. Presented “Shape Optimization for DIII-D Ad- at the Sixth International Symposium on vanced Tokamak Plasmas,” in the Pro- Fusion Nuclear Technology (ISFNT-6) (7- ceedings of the 30th European Physical 12 April 2002, San Diego, California). Society Conference on Controlled Fusion and Plasma Physics (7-11 July 2003, Kaita, R., Majeski, R., Doerner, R., Antar, St. Petersburg, Russia), Europhysics G., Baldwin, M., Conn, R., Efthimion, P., Conference Abstracts 27A (European Finkenthal, M., Hoffman, D., Jones, B., Physical Society, 2003) paper P-4.44. Krashenninikov, Kugel, H., Luckhardt, This conference proceedings is published S., Maingi, R., Menard, J., Munsat, T., on CD-ROM. Papers available in PDF Stutman, D., Taylor, G., Timberlake, J., format at http://eps2003.ioffe.ru/ (as of Soukhanovskii, V., Whyte, D., Woolley, 12 November 2003). Princeton Plasma R., and Zakharov, L., “Liquid Lithium Physics Laboratory Report PPPL-3848 Limiter Effects on Tokamak Plasmas (July 2003) 4 pp. and Plasma-liquid Surface Interactions” Princeton Plasma Physics Laboratory Kessel, C.E., Meade, D., and Jardin, Report PPPL-3755 (October 2002) 5 pp. S.C., “Physics Basis and Simulation of Presented at the Nineteenth IAEA Fusion Burning Plasma Physics for the Fusion

177 Ignition Research Experiment (FIRE),” §Kramer, G.J., Sharapov, S.E., Nazikian, Fusion Eng. Des. 63-64 (December R., Gorelenkov, N.N., Budny, R., and 2002) 559-567; Princeton Plasma Phys- contributors to the Joint European ics Laboratory Report PPPL-3646 (Jan- Torus, “Observation of Odd Toroidal uary 2002) 20 pp. Presented at the Alfvén Eigenmodes,” Phys. Rev. Lett. 92 Sixth International Symposium on Fusion (9 January 2004) 015001/1-4; Princeton Nuclear Technology (ISFNT-6) (7-12 Plasma Physics Laboratory Report April 2002, San Diego, California). PPPL-3768 (January 2003) 10 pp (title: First Evidence for the Existence of Odd Klasky, S., Ethier, S., Lin, Z., Martins, Toroidal Alfvén Eigenmodes (TAEs) from K., McCune, D., and Samtaney, R., the Simultaneous Observation of Even “Grid-based Parallel Data Streaming and Odd TAEs on the Joint European Implemented for the Gyrokinetic Toroidal Torus). Code,” in the Proceedings of the SC2003 Igniting Innovation Conference (15-21 No- *Krasheninnikov, S.I., Zakharov, L.E., vember 2003, Phoenix, Arizona); Prince- and Pereverzev, G.V., “On Lithium Walls ton Plasma Physics Laboratory Report and the Performance of Magnetic Fusion PPPL-3868 (September 2003) 10 pp. Devices,” Phys. Plasmas 10 (May 2003) 1678-1682. *Kolesnichenko, Ya.I., Marchenko, V.S., and White, R.B., “Infernal Fishbone *Krasik, Y.E., Chirko, K., Dunaevsky, A., Mode,” Princeton Plasma Physics Lab- Gleizer, J.Z., Krokhmal, A., Sayapin, A., oratory Report PPPL-3786 (February and Felsteiner, J., “Ferroelectric Plasma 2003) 9 pp; submitted to Physics of Plas- Sources and their Applications,” IEEE mas. Trans. Plasma Sci. 31 (February 2003) 49-59. *Kolesnichenko, Ya.I., White, R.B., and Yakovenko, Yu.V., “Precession of *†Kremer, J.P., Pedersen, T.S., Pomphrey, Toroidally Passing Particles in Tokamaks N., Reiersen, W., and Dahlgren, F., “The and Spherical Tori,” Phys. Plasmas 10 Status of the Design and Construction (May 2003) 1449-1457; Princeton Plas- of the Columbia Non-neutral Torus,” ma Physics Laboratory Report PPPL- AIP Conference Proceedings 692 (2 3775 (January 2003) 25 pp. December 2003) 320-325. Presented at the 2003 Workshop on Non-neutral Kramer, G.J., Nazikian, R., and Valeo, Plasmas (7-11 July 2003, Santa Fe, New E., “Correlation Reﬂ ectrometry for Mexico). Turbulence and Magnetic Field Mea- surements in Fusion Plasmas,” Rev. Sci. Ku, L.P., Zarnstorff, M., White, R.B., Instrum 74 (March 2003) 1421-1425; Cooper, W.A., Sanchez, R., Neilson, Princeton Plasma Physics Laboratory H., and Schmidt, J.A., “Development Report PPPL-3722 (July 2002) 22 pp. of Compact Quasi-Axisymmetric Stel- Presented at the Fourteenth APS Topical lar ator Reactor Conﬁ gurations,” in the Conference on High Temperature Plasma Proceedings of the 14th International Diagnostics (8-10 July 2002, Madison, Stellarator Workshop (22-26 September Wisconsin). 2003, Greifswald, Germany) P.Tul3;

178 Proceedings to be published on a CD- keV Negative-ion-based Neutral Beam ROM. Papers available at http://www. Injection System for JT-60U,” Fusion ipp.mpg.de/eng/for/veranstaltungen/ Sci. Technol. 42 (September-November workshops/stellarator_2003/SWS- 2002) 410-423. CDROM/papers/papers_alphabetic. html (as of 15 May 2004). Princeton LeBlanc, B.P., Bell, M.G., Bell, R.E., Plasma Physics Laboratory Report PPPL- Bitter, M.L., Bourdelle, C., Gates, D.A., 3874 (September 2003) 6 pp. Kaye, S.M., Maingi, R., Menard, J.E., Mueller, D., Ono, M., Paul, S.F., Redi, *Kubota, S., Peebles, W.A., Nguyen, M.H., Roquemore, A.L., Rosenberg, X.V., and Roquemore, A.L., “Automatic A., Sabbagh, S.A., Stutman, D., Syna- Profi le Reconstruction for Millimeter- kowski, E.J., Soukhanovskii, V.A., and wave Frequency-modulated Continuous- Wilson, J.R., “Transport in Auxiliary wave Refl ectometry on NSTX,” Rev. Sci. Heated NSTX Discharges,” in the Instrum. 74 (March 2003) 1477-1480. Proceedings of the 30th European Physical Society Conference on Controlled Fusion Kugel, H.W., Spong, D., Majeski, R., and Plasma Physics (7-11 July 2003, and Zarnstorff, M., “Chapter 6: NCSX St. Petersburg, Russia), Europhysics Plasma Heating Methods,” Princeton Con ference Abstracts 27A (European Plasma Physics Laboratory Report Physical Society, 2003) paper P-3.98. PPPL-3792 (February 2003) 46 pp. This conference proceedings is published To be published in Fusion Science and on CD-ROM. Papers available in PDF Technology, Special Issue - NCSX. format at http://eps2003.ioffe.ru/ (as of 12 November 2003). Princeton Plasma Kugel, H.W., Soukhanovskii, V., Bell, Physics Laboratory Report PPPL-3837 M., Blanchard, W., Gates, D., LeBlanc, (July 2003) 4 pp. B., Maingi, R., Mueller, D., Na, H.K., Paul, S., Skinner, C.H., Stutman, D., LeBlanc, B.P., Bell, M.G., Bell, R.E., and Wampler, W.R., “Impact of Wall Bitter, M.L., Bourdelle, C., Gates, D.A., Conditioning Program on Plasma Kaye, S.M., Maingi, R., Menard, J.E., Performance in NSTX,” J. Nucl. Mater. Mueller, D., Paul, S.F., Roquemore, A.L., 313-316 (March 2003) 187-193; Prince- Rosenberg, A., Sabbagh, S.A., Stutman, ton Plasma Physics Laboratory Report D., Synakowski, E.J., Soukhanovskii, PPPL-3725 (July 2002) 14 pp. Presented V.A., Wilson, J.R., and the NSTX Re- at the 15th International Conference on search Team, “Confi nement Studies Plasma Surface Interactions in Controlled of Auxiliary Heated NSTX Plasmas,” Fusion Devices (PSI-15) (27-31 May Princeton Plasma Physics Laboratory 2002, Gifu, Japan). Report PPPL-3810 (May 2003) 38 pp; submitted to Nuclear Fusion. *Kuriyama, M., Akino, N., Ebisawa, N., Grisham, L.R., Honda, A., Itoh, T., Kawai, LeBlanc, B.P., Bell, R.E., Johnson, M., Kazawa, M., Mogaki, K., Ohara, D.W., Hoffman, D.E., Long, D.C., and Y., Ohga, T., Okumura, Y., Oohara, Palladino, R.W., “Operation of the NSTX H., Umeda, N., Usui, K., Watanabe, Thomson Scattering System,” Rev. Sci. K., Yamamoto, M., and Yamamoto, T., Instrum. 74 (March 2003) 1659-1662; “Operation and Development of the 500 Princeton Plasma Physics Laboratory

179 Report PPPL-3745 (August 2002) 13 pp. 1200. Presented at the Fourteenth APS Presented at the Fourteenth APS Topical Topical Conference on High Temperature Conference on High Temperature Plasma Plasma Diagnostics (8-10 July 2002, Diagnostics (8-10 July 2002, Madison, Madison, Wisconsin). Wisconsin). *Lee, S.G., Bak, J.G., Jung, Y.S., Bitter, †LeBlanc, B.P., Bell, R.E., Bernabei, M., Hill, K.W., Hoelzer, G., Wehrhan, S.I., Indireshkumar, K., Kaye, S.M., O., and Foerster, E., “A New Method Maingi, R., Mau, T.K., Swain, D.W., for Simultaneous Measurement of Taylor, G., Ryan, P.M., Wilgen, J.B., and the Integrated Refl ectivity of Crystals Wilson, J.R., “High-harmonic Fast Wave at Multiple Orders of Refl ection and Driven H-mode Plasmas on NSTX,” Comparison with New Theoretical Cal- AIP Conference Proceedings 694 (15 culations,” Princeton Plasma Physics December 2003) 201-204; Princeton Laboratory Report PPPL-3803 (March Plasma Physics Laboratory Report 2003) 29 pp; submitted to Review of PPPL-3816 (May 2003) 4 pp. Presented Scientifi c Instruments. at the 15th AIP Topical Conference on Radio Frequency Power in Plasmas (19-21 Lee, W.W., “Theoretical and Numerical May 2003, Grand Teton National Park, Properties of a Gyrokinetic Plasma: Moran, Wyoming). Issues Related to Transport Time Scale Simulation,” Princeton Plasma *Lee, J., Gallagher, P.T., Gary, D.E., Nita, Physics Laboratory Report PPPL-3873 G.M., Choe, G.S., Bong, S.C., and Yun, (September 2003) 12 pp. Presented at H.S., “Hα, Extreme-ultraviolet, and Mi- the 18th International Conference on Nu- cro wave Observations of the 2000 March merical Simulation of Plasmas (ICNSP 22 Solar Flare and Spontaneous Magnetic ’03) (7-10 September 2003, Cape Cod, Reconnection,” Astrophys. J. 585 (March Massachusetts); submitted to Computer 2003) 524-535. Physics Communications.

*Lee, K.C., Domier, C.W., Deng, B.H., Lee, W.W. and Qin, H., “Alfvén Waves Johnson, M., Nathan, B.R., Luhmann, in Gyrokinetic Plasmas,” Phys. Plasmas N.C., Jr., and Park, H., “A Stark-tuned 10 (August 2003) 3196-3203; Princeton Laser Application for Interferometry and Plasma Physics Laboratory Report PPPL- Polarimetry on the National Spherical 3806 (April 2003) 24 pp. Torus Experiment,” Rev. Sci. Instrum. 74 (March 2003) 1621-1624. Presented §Lewandowski, J.L.V., “Gyrokinetic at the Fourteenth APS Topical Conference Simulations of Microinstabilities in Stel- on High Temperature Plasma Diagnostics larator Geometry,” Phys. Plasmas 10 (8-10 July 2002, Madison, Wisconsin). (October 2003) 4053-4063; Princeton Plasma Physics Laboratory Report PPPL- *Lee, S.G., Bak, J.G., Bitter, M., Moon, 3861 (August 2003) 39 pp. M.K., Nam, U.W., Jin, K.C., Kong, K.N., and Seon, K.I., “Imaging X-ray Lewandowski, J.L.V., “Improved Con- Crystal Spectrometers for KSTAR,” Rev. ser vation Properties for Particle-in-cell Sci. Instrum. 74 (March 2003) 1997- Simulations with Kinetic Electrons,”

180 Plasma Phys. Control. Fusion 45 (July Barriers in JET,” presented at the 2003) L39-L46; Princeton Plasma Phys- Nineteenth IAEA Fusion Energy Conference ics Laboratory Report PPPL-3826 (June (14-19 October 2002, Lyon, France). 2003) 13 pp. Lukin, V.S. and Jardin, S.C., “Hall Lewandowski, J.L.V., “Multigrid Par ti- MHD Modeling of Two-dimensional cle-in-cell Simulations of Plasma Micro- Reconnection: Application to MRX Ex- turbulence,” Phys. Plasmas 10 (August per iment,” Phys. Plasmas 10 (August 2003) 3204-3211; Princeton Plasma 2003) 3131-3138; Princeton Plasma Physics Laboratory Report PPPL-3823 Physics Laboratory Report PPPL-3765 (June 2003) 30 pp. (January 2003) 18 pp.

Lewandowski, J.L.V., “Neural Network *Lund, S.M., Barnard, J.J., Davidson, Algorithm for Particle Loading,” Prince- R.C., and Lee, E.P., “Beam Emittance ton Plasma Physics Laboratory Report Growth from the Collective Relaxation PPPL-3808 (April 2003) 15 pp; sub- of Space-Charge Nonuniformities,” submitted to Physics Letters A. mitted for publication (2002).

Lewandowski, J.L.V., “Numerical *Lyon, J.F., Hirshman, S.P., Spong, D.A., Loading of a Maxwellian Probability Strickler, D.J., Nelson, B.E., Ware, A.S., Distribution Function,” Can. J. Phys. Williamson, D.E., Berry, L.A., Cole, 81 (August 2003) 989-996; Princeton M.J., Fogarty, P.J., Mioduszewski, P.K., Plasma Physics Laboratory Report PPPL- Monticello, D.A., Fu, G.Y., Mikkelsen, 3798 (March 2003) 18 pp. D., Barcikowski, E., and Westerly, D., “Overview of the QPS Project,” in the §Lewandowski, J.L.V., “Strange Attractors Proceedings of the 30th European Physical in Drift Wave Turbulence,” Canadian J. Society Conference on Controlled Fusion Phys. 81 (December 2003) 1331-1341; and Plasma Physics (7-11 July 2003, Princeton Plasma Physics Laboratory Re- St. Petersburg, Russia), Europhysics port PPPL-3807 (April 2003) 20 pp. Conference Abstracts 27A (European Physical Society, 2003) paper P-4.12. Lewandowski, J.L.V., “Strange Attractors This conference proceedings is published in Drift Wave Turbulence,” Princeton on CD-ROM. Papers available in PDF Plasma Physics Laboratory Report PPPL- format at http://eps2003.ioffe.ru/ (as of 3863 (September 2003) 6 pp. Presented 12 November 2003). at the 18th International Conference on Numerical Simulation of Plasmas (7- *Maddison, G.P., Brix, M., Budny, R., 10 September 2003, Cape Cod, Mas sa- Charlet, M., Coffey, I., and 38 additional chusetts); submitted to Computer Phys- co-authors including J. Strachan of ics Communications. PPPL), “Impurity-seeded Plasma Ex periments on JET,” Nucl. Fusion 43 (De- *Litaudon, X., Bécoulet, A., Crisanti, F., cember 2002) 49-62. Wolf, R.C., Baranov, Yu.F., Barbato, E., Bécoulet, M., Budny, R., et al., “Progress *Maingi, R., Bell, M., Bell, R., Biewer, T., Towards Steady-state Operation and Bush, C., Chang, C.S., Gates, D., Kaye, Real Time Control of Internal Transport S., LeBlanc, B., Maqueda, R., Menard,

181 J., Mueller, D., Raman, R., Sabbagh, S., E.J., Tan, T., Wilgen, J.B., and Zweben, Soukhanovskii, V., and the NSTX Team, S.J., “H-mode Research in NSTX,” Nucl. “Effect of Fueling Location on H-mode Fusion 43 (September 2003) 969-974. Access in NSTX,” in the Proceedings of the Presented at the Nineteenth IAEA Fusion 30th European Physical Society Conference Energy Conference (14-19 October 2002, on Controlled Fusion and Plasma Physics Lyon, France). (7-11 July 2003, St. Petersburg, Russia), Europhysics Conference Abstracts 27A *Maingi, R., Kugel, H.W., Lasnier, (European Physical Society, 2003) paper C.J., Roquemore, A.L., Soukhanovskii, P-3.97. This conference proceedings is V.A., and Bush, C.E., and the NSTX published on CD-ROM. Papers available Team, “Heat Flux Scaling Experiments in PDF format at http://eps2003.ioffe. in NSTX,” J. Nucl. Mater. 313-316 ru/ (as of 12 November 2003). (March 2003) 1005-1009. Presented at the 15th International Conference on *Maingi, R., Bell, M.G., Bell, R.E., Plasma Surface Interactions in Controlled Bialek, J., Bourdelle, C., Bush, C.E., Fusion Devices (PSI-15) (27-31 May Darrow, D.S., Fredrickson, E.D., Gates, 2002, Gifu, Japan). D.A., Gilmore, M., Gray, T., Jarboe, T.R., Johnson, D.W., Kaita, R., Kaye, Majeski, R., Boaz, M., Hoffman, D., S.M., Dubota, S., Kugel, H.W., LeBlanc, Jones, B., Kaita, R., Kugel, H., Munsat, B.P., Maqueda, R.J., Mastrovito, D., T., Spaleta, J., Soukhanovskii, V., Tim- Medley, S.S., Menard, J.E., Mueller, berlake, J., Zakharov, L., Antar, G., D., Nelson, B.A., Ono, M., Paoletti, Doerner, R., Luckhardt, S., Conn, F., Park, H.K., Paul, S.F., Peebles, T., R.W., Finkenthal, M., Stutman, D., Peng, Y.-K.M., Phillips, C.K., Raman, Maingi, R., and Ulrickson, M., “CDX- R., Rosenberg, A.L., Roquemore, A.L., U Operation with a Large Area Liquid Ryan, P.M., Sabbagh, S.A., Skinner, Lithium Limiter,” J. Nucl. Mater. 313- C.H., Soukhanovskii, V.A., Stutman, D., 316 (March 2003) 625-629; Princeton Swain, D.W., Synakowski, E.J., Taylor, Plasma Physics Laboratory Report PPPL- G., Wilgen, J., Wilson, J.R., Wurdern, 3727 (July 2002) 14 pp. Presented at the G.A., Zweben, S.J., and the NSTX 15th International Conference on Plasma Team, “Recent Results from the National Surface Interactions in Controlled Fusion Spherical Torus Experiment,” Plasma Devices (PSI-15) (27-31 May 2002, Gifu, Phys. Control Fusion 45 (May 2003) Japan). 657-669. Majeski, R., Boaz, M., Hoffman, D., *Maingi, R., Bell, M.G., Bell, R.E., Bush, Jones, B., Kaita, R., Kugel, H., Munsat, C.E., Fredrickson, E.D., Gates, D.A., T., Spaleta, J., Soukhanovskii, V., Gray, T., Johnson, D.W., Kaita, R., Kaye, Timberlake, J., Zakharov, L., Antar, G., S.M., Kubota, S., Kugel, H.W., Lasnier, Doerner, R., Luckhardt, S., Conn, R.W., C.J., LeBlanc, B.P., Maqueda, R.J., Finkenthal, M., Stutman, D., Maingi, R., Mastrovito, D., Menard, J.E., Mueller, and Ulrickson, M., “Plasma Performance D., Ono, M., Paoletti, F., Paul, S.J., Peng, Improvements with Liquid Lithium Y.-K.M., Roquemore, A.L., Sabbagh, Limiters in CDX-U,” Fusion Eng. Des. S.A., Skinner, C.H., Soukhanovski, V.A., 65 (April 2003) 443-447; Princeton Stutman, D., Swain, D.W., Synakowski, Plasma Physics Laboratory Report

182 PPPL-3726 (July 2002) 16 pp. Presented (FIRE),” in the Proceedings of the 30th at the First International Workshop on In- European Physical Society Conference on novative Concepts for Plasma-interactive Controlled Fusion and Plasma Physics (7- Components in Fusion Devices (23-25 11 July 2003, St. Petersburg, Russia), May 2002, Osaka, Japan). Europhysics Conference Abstracts 27A (European Physical Society, 2003) paper *Maqueda, R.J., Wurden, G.A., Stotler, O-3.5A. This conference proceedings is D.P., Zweben, S.J., LaBombard, B., published on CD-ROM. Papers available Terry, J.L., Lowrance, J.L., Mastrocola, in PDF format at http://eps2003.ioffe. V.J., Renda, G.F., D’Ippolito, D.A., ru/ (as of 12 November 2003). Myra, J.R., and Nishino, N., “Gas Puff Imaging of Edge Turbulence,” Rev. Sci. Medley, S.S., Bell, R.E., Fredrickson, E.D., Instrum. 74 (March 2003) 2020-2026. and Roquemore, A.L., “Energetic Ion Presented at the Fourteenth APS Topical Behavior in the National Spherical Torus Conference on High Temperature Plasma Experiment,” in the Proceedings of the Diagnostics (8-10 July 2002, Madison, 30th European Physical Society Conference Wisconsin). on Controlled Fusion and Plasma Physics (7-11 July 2003, St. Petersburg, Russia), *Mase, A., Kogi, Y., Kawahata, K., Europhysics Conference Abstracts 27A Nagayama, Y., Luhmann, N.C., Jr., (European Physical Society, 2003) paper Deng, B.H., Domier, C.W., Mazzucato, P-4.96. This conference proceedings is E., Munsat, T., and Park, H.K., “Pro- published on CD-ROM. Papers available gress in Millimeter-wave Imaging Di- in PDF format at http://eps2003.ioffe. ag nostics,” Fusion Sci. Technol. 43 ru/ (as of 12 November 2003). Princeton (January 2003) 237-242; Presented at the Plasma Physics Laboratory Report PPPL- Fourth International Conference on Open 3827 (June 2003) 7 pp. Magnetic Systems for Plasma Conﬁ nement (OS2002) (1-4 July 2002, Jeju Island, Medley, S.S., Bell, R.E., Petrov, M.P., Korea). Roquemore, A.L., and Suvorkin, E.V., “Initial Neutral Particle Analyzer Mea- §Mastrovito, D., Maingi, R., Kugel, H.W., surements of Ion Temperature in the and Roquemore, A.L., “Infrared Camera National Spherical Torus Experiment,” Diagnostic for Heat Flux Measurements Rev. Sci. Instrum. 74 (March 2003) on NSTX,” Rev. Sci. Instrum. 74 (De- 1896-1899; Princeton Plasma Physics cember 2003) 5090-5092; Princeton Lab oratory Report PPPL-3718 (July Plas ma Physics Laboratory Report PPPL- 2002) 10 pp. Presented at the Fourteenth 3801 (March 2003) 12 pp. APS Topical Conference on High Tem- perature Plasma Diagnostics (8-10 July Meade, D.M., Kessel, C.E., Ulrickson, 2002, Madison, Wisconsin). M.A., Navratil, G.A., Bialek, J., Swain, D.W., Bonoli, P., Mau, T.K., Jardin, Menard, J.E., Bell, M.G., Bell, R.E., S.C., Young, K.M., Heitzenroeder, P., Fredrickson, E.D., Gates, D.A., Kaye, Nelson, B.E., Thome, R.J., and Schmidt, S.M., LeBlanc, B.P., Maingi, R., Mueller, J.A., “Advanced Tokamak Regimes in the D., Sabbagh, S.A., Stutman, D., Bush, Fusion Ignition Research Experiment C.E., Johnson, D.W., Kaita, R., Kugel,

183 H.W., Maqueda, R.J., Paoletti, F., Paul, perature Proﬁ les in JT-60U ELMy H- S.F., Ono, M., Peng, Y.-K.M., Skinner, mode Plasmas,” Nucl. Fusion 43 (Jan- C.H., Synakowski, E.J., and the NSTX uary 2003) 30-39; Princeton Plasma Research Team, “Beta-limiting MHD Physics Laboratory Report PPPL-3620 Instabilities in Improved-performance (October 2001) 19 pp. NSTX Spherical Torus Plasmas,” Nucl. Fusion 43 (May 2003) 330-340; *Moon, Y.-J., Chae, J., Wang, H., Princeton Plasma Physics Laboratory Choe, G.S., and Park, Y.D., “Impulsive Report PPPL-3815 (May 2003) 14 pp. Variations of the Magnetic Helicity Change Rate Associated with Eruptive Menard, J.E., Bell, M.G., Bell, R.E., Flares,” Astrophys. J. 580 (November Gates, D.A., Kaye, S.M., LeBlanc, B.P., 2002) 528-537. Sabbagh, S.A., Fredrickson, E.D., Jardin, S.C., Maingi, R., Manickam, J., Mueller, *Moon, Y.-J., Choe, G.S., Wang, H., D., Ono, M., Paoletti, F., Peng, Y.- and Park, Y.D., “Sympathetic Coronal K.M., Soukhanovskii, V., Stutman, D., Mass Ejections,” Astrophys. J. 588 (May Synakowski, E.J., and the NSTX research 2003) 1176-1182. team, “Uniﬁ ed Ideal Stability Limits for Advanced Tokamak and Spherical Torus *Moon, Y.-J., Choe, G.S., Wang, H., Plasmas,” Princeton Plasma Physics Park, Y.D., and Cheng, C.Z., “Relation- Laboratory Report PPPL-3779 (February ship Between CME Kinematics and Flare 2003) 4 pp; submitted to Physical Review Strength,” Journal of the Korean Astro- Letters. nomical Society 36 (June 2003) 61-66.

Menard, J.E., Park, W., Bell, R.E., *Moon, Y.-J., Choe, G.S., Wang, Haimin, Fredrickson, E.D., Gates, D.A., Kaye, Park, Y.D., Gopalswamy, N., Yang, Guo, S.M., LeBlanc, B.P., Sabbagh, S.A., and Yashiro, S., “A Statistical Study of Stutman, D., and the NSTX National Two Classes of Coronal Mass Ejections,” Research Team, “Saturation of Internal Astrophys. J. 581 (December 2002) 694- Kink Modes in High-β NSTX Plasmas,” 702. in the Proceedings of the 30th European Physical Society Conference on Controlled †Morrison, Kyle A.; Paul, Stephen F.; and Fusion and Plasma Physics (7-11 July Davidson, Ronald C., “Measurements of 2003, St. Petersburg, Russia), Europhysics Plasma Expansion due to Background Conference Abstracts 27A (European Gas in the Electron Diffusion Gauge Physical Society, 2003) paper P-3.101. Experiment,” AIP Conference Pro ceed- This conference proceedings is published ings 692 (2 December 2003) 75-80; on CD-ROM. Papers available in PDF Princeton Plasma Physics Laboratory format at http://eps2003.ioffe.ru/ (as of Report PPPL-3853 (August 2003) 6 pp. 12 November 2003). Presented at the 2003 Workshop on Non- neutral Plasmas (7-11 July 2003, Santa Mikkelsen, D.R., Shirai, H., Urano, Fe, New Mexico). H., Takizuka, T., Kamada, Y., Hatae, T., Koide, Y., Asakura, N., Fujita, T., Mueller, D., Grisham, L., Kaganovich, Fukuda, T., Ide, S., Isayama, A., Kawano, I., Watson, R.L., Horvat, V., Zaharakis, Y., Naito, O., Sakamota, Y., “Stiff Tem- K.E., and Peng, Y., “Multiple Electron

184 Stripping of Heavy Ions Beams,” Laser G.M., Taylor, T.S., Austin, M.E., Baker, and Particle Beams 20 (October 2002) D.R., Budny, R.V., and 20 additional co- 551-554; Princeton Plasma Physics authors including D. McCune of PPPL, Laboratory Report PPPL-3713 (June “Advanced Tokamak Profi le Evolution in 2002) 12 pp. DIII-D,” Phys. Plasmas 10 (May 2003) 1691-1697. Mueller, D., Ono, M., Bell, M.G., Bell, R.E., Bitter, M., Bourdelle, C., Darrow, *Najmabadi, F. and The ARIES Team (of D.S., Efthimion, P.C., Fredrickson, E.D., which PPPL is a participant), “Spherical Gates, D.A., Goldston, R.J., Grisham, Torus Concept as Power Plants — The L.R., Hawryluk, R.J., plus 75 additional ARIES-ST Study,” Fusion Eng. Des. 65 co-authors, “Results of NSTX Heating (February 2003) 143-164. Experiments,” IEEE Trans. Plasma Sci. 31 (February 2003) 60-67; Princeton Nazikian, R., Kramer, G.J., Cheng, Plasma Physics Laboratory Report PPPL- C.Z., Gorelenkov, N.N., Berk, H.L., and 3709 (June 2002) 13 pp. Presented at the Sharapov, S.E., “A New Interpretation 29th IEEE International Conference on of Alpha-particle-driven Instabilities in Plasma Science (27-30 May 2002, Banff, Deuterium-tritium Experiments on the Alberta, Canada). Tokamak Fusion Reactor,” Phys. Rev. Lett. 91 (19 September 2003) 125003/1- Munsat, T., Mazzucato, E., Park, H., 4; Princeton Plasma Physics Laboratory Deng, B.H., Domier, C.W., Luhmann, Report PPPL-3800 (March 2003) 15 pp. N.C., Jr., Wang, J., Xia, Z.G., Donné, A.J.H., and van de Pol, M., “Microwave Neilson, G.H., Zarnstorff, M.C., Ku, Imaging Refl ectometer for TEXTOR L.P., Lazarus, E.A., Mioduszewski, P.K., (invited),” Rev. Sci. Instrum 74 (March Fenstermacher, M., Fredrickson, E., Fu, 2003) 1426-1432; Princeton Plasma G.Y., Grossman, A., Heitzenroeder, P.J., Physics Laboratory Report PPPL-3721 Hatcher, R.H., Hirshman, S.P., Hudson, (July 2002) 8 pp. Presented at the Four- S.R., Johnson, D.W., Kugel, H.W., teenth APS Topical Conference on High Lyon, J.F., Majeski, R., Mikkelsen, Tem perature Plasma Diagnostics (8-10 D.R., Monticello, D.A., Nelson, B.E., July 2002, Madison, Wisconsin). Pomphrey, N., Reiersen, W.T., Reiman, A.H., Rutherford, P.H., Schmidt, J.A., Munsat, T., Mazzucato, E., Park, H., Spong, D.A., and Strickler, D.J., “Physics Domier, C.W., Luhmann, N.C., Jr., Considerations in the Design of NCSX” Donné, A.J.H., and van de Pol, M., “Lab- Princeton Plasma Physics Laboratory oratory Characterization of an Imag ing Report PPPL-3753 (October 2002) 8 pp. Refl ectometer System,” Plasma Phys. Presented at the Nineteenth IAEA Fusion Control. Fusion 45 (April 2003) 469- Energy Conference (14-19 October 2002, 487; Princeton Plasma Physics Lab o ra- Lyon, France). tory Report PPPL-3767 (January 2003) 24 pp. Neumeyer, C., Heitzenroeder, P., Kessel, C., Ono, M., Peng, M., Schmidt, J., *Murakami, M., Wade, M.R., DeBoo, Woolley, R., and Zatz, I., “Next Step J.C., Greenfi eld, C.M., Luce, T.C., Spherical Torus Design Studies,” Fusion Makowski, M.A., Petty, C.C., Staebler, Eng. Des. 66-68 (September 2003) 139-

185 145; Princeton Plasma Physics Laboratory “Determination of Diameter and Index Report PPPL-3761 (November 2002) of Refraction of Textile Fibers by Laser 4 pp. Presented at the 22nd Symposium Backscattering,” Princeton Plasma Phys- on Fusion Technology (SOFT 2002) (9- ics Laboratory Report PPPL-3842 (July 13 September 2002, Marina Congress 2003) 33 pp. Center, Helsinki, Finland). *Ongena, J., Suttrop, W., Bécoulet, M., *Noterdaeme, J.-M., Budny, R., Cardinali, Cordey, G., Dumortier, P., Eich, Th., A., Castaldo, C., Cesario, R., and 31 Ingesson, L.C., Jachmich, S., Lang, P., additional co-authors, “Heating, Current Loarte, A., Lomas, P., Maddison, G.P., Drive and Energetic Particles Studies on Messiaen, A., Nave, M.F.F., Rapp, J., JET in Preparation of ITER Operation,” Saibene, G., Sartori, R., Sauter, O., Nucl. Fusion 43 (March 2003) 202-209. Strachan, J.D., Unterberg, B., Valovic, Presented at the Nineteenth IAEA Fusion M., Alper, B., Andrew, Ph., Baranov, Energy Conference (14-19 October 2002, Y., Brzozowski, J., Bucalossi, J., Brix, Lyon, France). M., Budny, R., et al., “Towards the Realization on JET of an Integrated H- *Ohdachi, S., Toi, K., Fuchs, G., mode Scenario for ITER,” presented von Goeler, S., Yamamoto, S., and at the Nineteenth IAEA Fusion Energy LHD Experiment Group, “High- Conference (14-19 October 2002, Lyon, speed Tangentially Viewing Soft X-ray France). Camera to Study Magnetohydrodynamic Fluctuations in Toroidally Confi ned Plas- *Pacella, D., Leigheb, M., Bellazzini, ma (invited),” Rev. Sci. Instrum. 74 R., Brez, A., Finkenthal, M., Stutman, (March 2003) 2136-12143. Presented at D., Kaita, R., and Sabbagh, S.A., “Soft the Fourteenth APS Topical Conference on X-ray Tangential Imaging of the NSTX High Temperature Plasma Diagnostics (8- Core Plasma by Means of a MPGD 10 July 2002, Madison, Wisconsin). Pin-hole Camera,” Princeton Plasma Physics Laboratory Report PPPL-3844 Okabayashi, M., Bialek, J., Chance, M.S., (July 2003) 18 pp; submitted to Plasma Chu, M.S., Fredrickson, E.D., Garofalo, Physics and Controlled Fusion. A.M., Hatcher, R., Jenson, T.H., John- son, L.C., LaHaye, R.J., Navratil, G.A., *Pacella, D., Pizzicaroli, G., Leigheb, M., Reimerder, H., Scoville, J.T., Strait, Bellazzini, R., Brez, A., Finkenthal, M., E.J., Turnbull, A.D., and Walker, M.L., Stutman, D., Blagojevic, B., Vero, R., “Stabilization of the Resistive Wall Kaita, R., Roquemore, A.L., and Johnson, Mode in DIII-D by Plasma Rotation D., “Fast X-ray Imaging of the National and Magnetic Feedback,” Plasma Phys. Spherical Tokamak Experiment Plasma Control. Fusion 44 (December 2002) with Micropattern Gas Detector Based on B339-B355. Presented at the 29th Gas Electron Multiplier Amplifi er,” Rev. European Physical Society on Plasma Sci. Instrum. 74 (March 2003) 2148- Physics and Controlled Fusion (17-21 June 2151. Presented at the Fourteenth APS 2002, Montreux, Switzerland). Topical Conference on High Temperature Plasma Diagnostics (8-10 July 2002, Okuda, H., Stratton, B., Meixler, Madison, Wisconsin). L., Efthimion, P. and Mansfi eld, D.,

186 Park, W., Breslau, J., Chen, J., Fu, and Transport on Electron Cyclotron G.Y., Jardin, S.C., Klasky, S., Menard, Current Drive on DIII-D,” Nucl. Fusion J., Pletzer, A., Stratton, B.C., Stutman, 43 (August 2003) 700-707. D., Strauss, H.R., and Sugiyama, L.E., “Nonlinear Simulation Studies of Toka- †Phillips, C.K., Pletzer, A., Dumont, maks and STs,” Nucl. Fusion 43 (June R.J., and Smithe, D.N., “Plasma Di- 2003) 483-489; Princeton Plasma Phys- elec tric Tensor for Non-Maxwellian ics Laboratory Report PPPL-3833 (July Dis tributions in the FLR Limit,” 2003) 7 pp. AIP Conference Proceedings 694 (15 December 2003) 499-502; Princeton Paul, S.F., “Real-time Plasma Rotation Plasma Physics Laboratory Report Diagnostic for Measuring Small Doppler PPPL-3835 (July 2003) 4 pp. Presented Shifts, “Rev. Sci. Instrum. 74 (March at the 15th AIP Topical Conference on 2003) 2098-2102. Radio Frequency Power in Plasmas (19-21 May 2003, Grand Teton National Park, †Paul, Stephen F.; Morrison, Kyle; and Moran, Wyoming). Davidson, Ronald C., “Experimental Investigation of m=1 Diocotron Mode *Pigarov, A.Yu., Krasheninnikov, S.I., Growth at Low Electron Densities,” AIP Rognlien, T.D., West, W.P., LaBombard, Conference Proceedings 692 (2 December B., Lipschultz, B., Maingi, R., and 2003) 81-86; Princeton Plasma Physics Soukhanovsky, V., “Analysis of Non- Laboratory Report PPPL-3859 (August diffusive Transport and SOL Recycling 2003) 6 pp. Presented at the 2003 with Multil-fl uid Plasma Code Workshop on Non-neutral Plasmas (7-11 UEDGE,” in the Proceedings of the 30th July 2003, Santa Fe, New Mexico). European Physical Society Conference on Controlled Fusion and Plasma Physics (7- *Pedersen, T. Sunn, Boozer, A.H., 11 July 2003, St. Petersburg, Russia), Kremer, J.P., Reiersen, W., Dahlgren, Europhysics Conference Abstracts 27A F., Pomphrey, N., Dorland, W., “The (European Physical Society, 2003) paper Columbia Non-neutral Torus, A New P-3.170. This conference proceedings is Experiment to Confi ne Nonneutral and published on CD-ROM. Papers available Positron-electron Plasmas in a Stellarator,” in PDF format at http://eps2003.ioffe. in the Proceedings of the 14th International ru/ (as of 12 November 2003). Stellarator Workshop (22-26 September 2003, Greifswald, Germany) I.Tu2; *Ping, Y., Geltner, I., Morozov, A., Proceedings to be published on a CD- Fisch, N.J., and Suckewer, S., “Raman ROM. Papers available at http://www. Amplifi cation of Ultrashort Laser Pulses ipp.mpg.de/eng/for/veranstaltungen/ in Microcapillary Plasma,” Phys. Rev. E. workshops/stellarator_2003/SWS- 66 (October 2002) 046401/1-6. CDROM/papers/papers_alphabetic. html (as of 15 May 2004). †Pletzer, A., Phillips, C.K., and Smithe, D.N., “Gabor Wave Packet Method to *Petty, C.C., Prater, R., Luce, T.C., Ellis, Solve Plasma Wave Equations,” AIP R.A., Harvey, R.W., Kinsey, J.E., Lao, Conference Proceedings 694 (15 De- L.L., Lohr, J., Makowski, M.A., and cember 2003) 503-506; Princeton Plas- Wong, K.L., “Effects of Electron Trapping ma Physics Laboratory Report PPPL-

187 3825 (June 2003) 4 pp. Presented at the Proton Beams,” Phys. Rev. ST Accel. 15th AIP Topical Conference on Radio Beams 6 (January 2003) Article No. Frequency Power in Plasmas (19-21 May 014401 (8 pages). 2003, Grand Teton National Park, Mo- ran, Wyoming). §Qin, Hong and Tang, W.M., “Pullback Trans formations in Gyrokinetic Theory,” Qin, H. and Davidson, R.C., “Study Phys. Plasmas 11 (March 2004) 1052- of Drift Compression for Heavy Ion 1063; Princeton Plasma Physics Lab- Beams,” Laser and Particle Beams 20 o ratory Report PPPL-3772 (January (October 2002) 565-568. 2003) 32 pp.

Qin, H., Davidson, R.C., Barnard, J.J., Raitses, Y., Keidar, M., Staack, D., and Lee, E.P., “Drift Compression and and Fisch, N.J., “Effects of Segmented Final Focus of Intense Heavy Ion Beams,” Electrode in Hall Current Plasma in the Proceedings of the 2003 Particle Thrusters,” J. Appl. Phys. 92 (1 Novem- Accelerator Conference (PAC2003) 4 (12- ber 2002) 4906-4911; Princeton Plasma 16 May 2003, Portland, Oregon) 2658- Physics Laboratory Report PPPL-3634 2660. (December 2001) 37 pp.

Qin, H., Davidson, R.C., Startsev, E.A., Raitses, Y., Staack, D., Dunaevsky, A., and Lee, W.W., “Delta-f Simulation Dorf, L., and Fisch, N.J., “Preliminary Studies of the Ion-Electron Two-Stream Results of Plasma Flow Measurements Instability in Heavy Ion Fusion Beams,” in a 2 kW Segmented Hall Thruster,” Laser and Particle Beams 21 (January Princeton Plasma Physics Laboratory 2003) 21-26. Report PPPL-3796 (March 2003) 10 pp; Presented at the 28th International Qin, H., Startsev, E.A., and Davidson, Electric Propulsion Conference (IEPC R.C., “Nonlinear Perturbative Simulation 2003) (17-21 March 2003, Toulouse, Studies of Two-Stream Interactions in France). Proceedings published on CD- Intense Charged Particle Beams,” pre- ROM. sented at the 2003 Particle Accelerator Conference (PAC2003) (12-16 May *Ramamurthi, B., Economou, D.J., 2003, Portland, Oregon), proceedings to and Kaganovich, I.D., “Effect of Non- be published. local Electron Conductivity on Power Absorption and Plasma Density Proﬁ les Qin, Hong, “Nonlinear δf Simulations in Low Pressure Inductively Coupled of Collective Effects in Intense Charged Discharges,” Plasma Sources Sci. Technol. Particle Beams,” Phys. Plasmas 10 (May 12 (May 2003) 170-181. 2003) 2078-2086; Princeton Plasma Physics Laboratory Report PPPL-3769 *Raman, R., Kugel, H.W., Provost, T., (January 2003) 21 pp. Gernhardt, R., Jarboe, T.R., and Bell, M.G., “Rev. Sci. Instrum. 74 (March Qin, Hong, Startsev, E.A., and Davidson, 2003) 1900-1904; Princeton Plasma R.C., “Nonlinear Perturbative Particle Si- Phys ics Laboratory Report PPPL-3732 mu lation Studies of the Electron-proton (August 2002) 5 pp. Presented at the Two-Stream Instability in High-Intensity Fourteenth APS Topical Conference on

188 High Temperature Plasma Diagnostics (8- §Rewoldt, G. and Kinsey, J.E., “Com- 10 July 2002, Madison, Wisconsin). parison of Linear Microinstability Cal culations of Varying Input Realism,” Phys. Redi, M.H., Dorland, W., Bell, R., Plasmas 11 (February 2004) 844-845; Bonoli, P., Bourdelle, C., Candy, J., Ernst, Princeton Plasma Physics Laboratory D., Fiore, C., Gates, D., Hammett, G., Report PPPL-3865 (September 2003) Hill, K., Kaye, S., LeBlanc, B., Menard, 5 pp. J., Mikkelsen, D., Rewoldt, G., Rice, J., Waltz, R., and Wukitch, S., “Gyrokinetic Roquemore, A.L., Darrow, D., Isobe, Calculations of Microturbulence and M., and Medley, S.S., “Design Concepts Transport for NSTX and Alcator-CMOD for a Multichannel neutron Collimator H-modes,” in the Proceedings of the 30th for the National Spherical Torus Ex per- European Physical Society Conference on iment,” in the Proceedings of the 30th Controlled Fusion and Plasma Physics (7- European Physical Society Conference on 11 July 2003, St. Petersburg, Russia), Controlled Fusion and Plasma Physics (7- Europhysics Conference Abstracts 27A 11 July 2003, St. Petersburg, Russia), (European Physical Society, 2003) paper Europhysics Conference Abstracts 27A P-4.94. This conference proceedings is (European Physical Society, 2003) paper published on CD-ROM. Papers available P-4.75. This conference proceedings is in PDF format at http://eps2003.ioffe. published on CD-ROM. Papers available ru/ (as of 12 November 2003). Princeton in PDF format at http://eps2003.ioffe. Plasma Physics Laboratory Report PPPL- ru/ (as of 12 November 2003). 3834 (July 2003) 4 pp. Rosenberg, A.L., Gates, D.A., Pletzer, A., Reiersen, W., Dahlgren, F., Fan, H.- Menard, J.E., Kruger, S.E., Hegna, C.C., M. Neumeryer, C., and Zatz, I., “The Paoletti, F., and Sabbagh, S., “Modeling Toroidal Field Coil Design for ARIES- of Neoclassical Tearing Mode Stability ST,” Fusion Eng. Des. 65 (February for Generalized Toroidal Geometry,” Phy. 2003) 303-322. Plasmas 9 (November 2002) 4567-4572; Princeton Plasma Physics Laboratory Re- *Reimerdes, H., Bialek, J., Chu, M.S., port PPPL-3740 (August 2002) 20 pp. Edgell, D.H., Garofalo, A.M., Jackson, G.L., Jensen, T.H., LaHaye, R.J., Navratil, †Rosenberg, A.L., Menard, J.E., Wilson, G.A., Okabayashi, M., Scoville, J.T., J.R., Medley, S., Phillips, C.K., Andre, R., Strait, E.J., and Turnbull, A.D., “Resistive Darrow, D.S., Dumont, R.J., LeBlanc, Wall Modes and Plasma Rotation in B.P., Redi, M.H., Mau, T.K., Jaeger, DIII-D,” in the Proceedings of the 30th E.F., Ryan, P.M., Swain, D.W., Harvey, European Physical Society Conference on R.W., Egedal, J., and the NSTX Team, Controlled Fusion and Plasma Physics (7- “Characterization of Fast Ion Absorption 11 July 2003, St. Petersburg, Russia), of the High Harmonic Fast Wave in the Europhysics Conference Abstracts 27A National Spherical Torus Experiment,” (European Physical Society, 2003) paper AIP Conference Proceedings 694 (15 P-4.45. This conference proceedings is December 2003) 185-192; Princeton published on CD-ROM. Papers available Plasma Physics Laboratory Report PPPL- in PDF format at http://eps2003.ioffe. 3854 (August 2003) 8 pp. Presented ru/ (as of 12 November 2003). at the 15th AIP Topical Conference on

189 Radio Frequency Power in Plasmas (19-21 Samtaney, Ravi, “Suppression of the May 2003, Grand Teton National Park, Richtmyer-Meshkov Instability in the Moran, Wyoming). Presence of a Magnetic Field,” Phys. Fluids 15 (August 2003) L53-L56; Prince- Rule, Keith; Kalb, Paul; and Kwaschyn, ton Plasma Physics Laboratory Report Pete, “Packaging and Disposal of Radium- PPPL-3794 (March 2003) 14 pp. beryllium Source using a Depleted Ura- nium Polyethylene Composite Shield- *Sartori, R., Saibene, G., Horton, L.D., ing Container,” Princeton Plasma Bécoulet, M., Budny, R., Borba, D., Phys ics Laboratory Report PPPL-3782 Chankin, A., Conway, G.D., Cordey, (February 2003) 11 pp. Presented at the G., McDonald, D., Guenter, K., von Waste Management Symposium 2003 (23- Hellermann, M.G., Igithkanov, Yu., 27 February 2003, Tucson, Arizona). Loarte, A., Lomas, P.J., Pogutse, O., and Rapp, J., “Study of Type III ELMs in Rule, Keith; Perry, Erik; Chrzanowski, JET,” submitted to Plasma Physics and Jim; Viola, Mike; and Strykowsky, Ron, Controlled Fusion. “The Innovations, Technology and Waste Management Approaches to Safely *Schekochihin, A.A., Cowley, S.C., Package and Transport the World’s First Hammett, G.W., Maron, J.L., and Radioactive Fusion Research Re actor McWilliams, J.C., “A Model of Nonlinear for Burial,” Princeton Plasma Physics Evolution and Saturation of the Turbulent Laboratory Report PPPL-3870 (Sep- MHD Dynamo,” New J. Phys. 4 (30 tember 2003) 5 pp. Presented at the Ninth October 2002) Article No. 84. International Conference on Environmental Remediation and Radioactive Waste Man- *Schekochihin, A.A., Cowley, S.C., agement (21-25 September 2003, Oxford, Taylor, S.F., Hammett, G.W., Maron, England). J.L., and McWilliams, J.C., “On the Saturated State of the Nonlinear Small- Rule, Keith; Perry, Erik; and Parsells, R., Scale Dynamo,” Phys. Rev. Lett. 92 (27 “Diamond Wire Cutting the Tokamak February 2004) Article No. 084504. Fusion Test Reactor,” Princeton Plasma Physics Laboratory Report PPPL-3776 †Schilling, G., Wukitch, S.J., Boivin, (January 2003) 9 pp. Presented at the R.L., Goetz, J.A., Hosea, J.C., Irby, Waste Management Symposium 2003 (23- J.H., Lin, Y., Parisot, A., Porkolab, 27 February 2003, Tucson, Arizona). M., Wilson, J.R., and the Alcator C- Mod Team, “Analysis of 4-strap ICRF *Sakakita, H., Craig, D., Anderson J.K., Antenna Performance in Alcator C- Biewer, T.M., Terry, S.D., Chapman, Mod,” AIP Conference Proceedings 694 B.E., Den-Hartog, D.J., Prager, S.C., (15 December 2003) 166-169; Princeton “Behavior of Impurity Ion Velocities Plasma Physics Laboratory Report PPPL- during the Pulsed Poloidal Current 3849 (July 2003) 4 pp. Presented at the Drive in the Madison Symmetric Torus 15th AIP Topical Conference on Radio- Reversed-ﬁ eld Pinch,” Jpn. J. Appl. frequency Power In Plasmas (19-21 May Phys. 42 (15 May 2003) L505-507 (Part 2003, Grand Teton National Park, 2, No. 5B). Moran, Wyoming).

190 *Schoepf, K., Yavorskij, V.A., Darrow, D., Laboratory Report PPPL-3843 (July Goloborod’ko, V.Ya., Gorelenkov, N., 2003) 20 pp. Holzmueller-Steinacker, U., Kaye, S.M., and Reznik, S.N., “Poincaré Mapping *Shu, W.M., Gentile, C.A., Skinner, for Non-adiabatic Variations of NBI C.H., Langish, S., and Nishi, M.F., Ions in NSTX,” in the Proceedings of the “The Effect of Oxygen on the Release 30th European Physical Society Conference of Tritium during Baking of TFTR on Controlled Fusion and Plasma Physics D-T Tiles,” Fusion Eng. Des. 61-62 (7-11 July 2003, St. Petersburg, Russia), (November 2002) 599-604. Presented Europhysics Conference Abstracts 27A at the Sixth International Symposium on (European Physical Society, 2003) paper Fusion Nuclear Technology (ISFNT-6) (8- P-4.95. This conference proceedings is 12 April 2002, San Diego, California). published on CD-ROM. Papers available in PDF format at http://eps2003.ioffe. Sichta, P., Dong, J., Marsala, R., Oliaro, ru/ (as of 12 November 2003). G., and Wertenbaker, J., “Developments to Supplant CAMAC with Industry *Semenov, I.B., Fredrickson, E.D., Standard Technology at NSTX,” Prince- Mirnov, S.V., and Vershkov, V.A., ton Plasma Physics Laboratory Report “Modes Dynamics in Precursor Phase PPPL-3850 (July 2003) 4 pp. Presented before Disruptive Instability,” in the at the 4th IAEA Technical Committee Proceedings of the 30th European Physical Meeting on Control, Data Acquisition, and Society Conference on Controlled Fusion Remote Participation for Fusion Research and Plasma Physics (7-11 July 2003, (21-23 July 2003, San Diego, California); St. Petersburg, Russia), Europhysics proceedings to be published by Fusion Conference Abstracts 27A (European Engineering and Design. Physical Society, 2003) paper P-3.158. This conference proceedings is published *Sips, A.C.C., Joffrin, E., deBaar, M., on CD-ROM. Papers available in PDF Barnsley, R., Budny, R., Buttery, R.J., format at http://eps2003.ioffe.ru/ (as of Challis, C.D., Giroud, C., Gruber, O., 12 November 2003). Hender, T.C., Hobirk, J., Litaudon, X., Maggi, C.F., Na, Y.-S., Pinches, *Semenov, I., Mirnov, S., Darrow, D., S.D., Stäbler, A., the ASDEX Upgrade Roquemore, L., Fredrickson, E.D., Team, and the EFDA-JET contributors, Menard, J., Stutman, D., and Belov, “Improved H-mode Identity Experiments A., “Phenomenology of Internal Recon- in JET and ASDEX Upgrade,” in the nections in NSTX,” Phys. Plasmas Proceedings of the 30th European Physical 10 (March 2003) 664-670; Princeton Society Conference on Controlled Fusion Plasma Physics Laboratory Report PPPL- and Plasma Physics (7-11 July 2003, 3702 (June 2002) 20 pp. St. Petersburg, Russia), Europhysics Conference Abstracts 27A (European §Sharma, Prateek; Hammett, Gregory Physical Society, 2003) paper O-1.3A. W.; and Quataert, Eliot, “Transition This conference proceedings is published from Collisionless to Collisional MRI,” on CD-ROM. Papers available in PDF Astrophys. J. 596 (1 October 2003) format at http://eps2003.ioffe.ru/ (as of 1121-1130; Princeton Plasma Physics 12 November 2003).

191 Skinner, C.H., Bekris, N., Coad, J.P., Smirnov, A., Raitses, Y., and Fisch, N.J., Gentlile, C.A., and Glugla, M., “Tritium “Enhanced Ionization in the Cylin drical Removal from JET and TFTR Tilesby Hall Thruster,” presented at the 28th a Scanning Laser,” J. Nucl. Mater. 313- International Electric Propulsion Con fer- 316 (March 2003) 496-500; Princeton ence (IEPC 2003) (17-21 March 2003, Plasma Physics Laboratory Report PPPL- Toulouse, France). Proceedings published 3697 (May 2002) 13 pp. Presented at the on CD-ROM. 15th International Conference on Plasma Surface Interactions in Controlled Fusion Smirnov, A., Raitses, Y., and Fisch, Devices (PSI-15) (27-31 May 2002, Gifu, N.J., “Parametric Investigations of Japan). Min i aturized Cylindrical and Annular Hall Thrusters,” J. Appl. Phys. 92 (15 Skinner, C.H., Bekris, N., Coad, J.P., November 2002) 5673-5679; Princeton Gentile, C.A., Hassanein, A., Reiswig, Plasma Physics Laboratory PPPL 3748 R., and Willms, S., “Thermal Response (September 2002) 29 pp. of Tritiated Codeposits from JET and TFTR to Transient Heat Pulses,” Physica Smirnov, A., Raitses, Y., and Fisch, N.J., Scripta T103 (2003) 34-37; Princeton “Plasma Measurements in a 100 W Plasma Physics Laboratory Report PPPL- Cylindrical Hall Thruster,” J. Appl. Phys. 3698 (May 2002) 16 pp. Presented at 95 (1 March 2004) 2283-2292. the International Workshop on Hydrogen Isotopes in Fusion Reactor Materials (22- Solodov, A.A., Malkin, V.M., and Fisch, 24 May 2002, Tokyo, Japan). N.J., “Random Density Inhomogeneities and Focusability of the Output Pulses for Skinner, C.H., Coad, J.P. and Federici, G., Plasma-based Powerful Backward Raman “Tritium Removal from Carbon Plasma Ampliﬁ ers,” Phys. Plasmas 10 (June Facing Components,” presented at the 2003) 2540-2544; Princeton Plasma 10th International Workshop on Carbon Physics Laboratory Report PPPL-3771 Materials for Fusion Application (17- (January 2003) 15 pp. 19 September 2003, Jülich, Germany), proceeding to be published in a special *Soukhanovskii, V.A., Finkenthal, M., issue of Physica Scripta. Moos, H.W., Stutman, D., Munsat, T., Jones, B., Hoffman, D., Kaita, R. and Skinner, C.H., Gentile, C.A., Ciebiera, Majeski, R., “Observation of Neoclassical L., and Langish, S., “Tritiated Dust Levi- Impurity Transport in Ohmically Heated tation by Beta Induced Static Charge,” Plasmas of CDX-U Low Aspect Ratio Princeton Plasma Physics Laboratory Tokamak,” Plasma Phys. Control. Fusion Report PPPL-3818 (June 2003) 15 pp; 44 (November 2002) 2339-2355. in press Fusion Science and Technology. Soukhanovskii, V.A., Maingi, R., Raman, Smirnov, A., Raitses, Y., and Fisch, N.J., R., Kugel, H., LeBlanc, B., Roquemore, “Enhanced Ionization in the Cylindrical A.L., Lasnier, C.J., and NSTX Research Hall Thruster,” J. Appl. Phys. 94 (15 Team, “Edge Recycling and Heat Fluxes July 2003) 852-857; Princeton Plasma in L- and H-mode NSTX Plasmas,” in the Physics Laboratory Report PPPL-3781 Proceedings of the 30th European Physical (February 2003) 25 pp. Society Conference on Controlled Fusion

192 and Plasma Physics (7-11 July 2003, (7-11 July 2003, St. Petersburg, Russia), St. Petersburg, Russia), Europhysics Europhysics Conference Abstracts 27A Conference Abstracts 27A (European (European Physical Society, 2003) paper Physical Society, 2003) paper P-3.179. P4.14. This conference proceedings is This conference proceedings is published published on CD-ROM. Papers available on CD-ROM. Papers available in PDF in PDF format at http://eps2003.ioffe. format at http://eps2003.ioffe.ru/ (as of ru/ (as of 12 November 2003). 12 November 2003). Princeton Plasma Physics Laboratory Report PPPL-3852 Staack, D., Raitses, Y., and Fisch, N.J., (August 2003) 4 pp. “Electrostatic Probe with Shielded Probe Insulator Tube for Low Disturbing Plas- Soukhanovskii, V.A., Roquemore, A.L., ma Measurements in Hall Thrusters,” Skinner, C.H., Menard, J., Kugel, H.W., Princeton Plasma Physics Laboratory Johnson, D., Maingi, R., Sabbagh, S., Report PPPL-3838 (July 2003) 31 and Paoletti, F., “High-resolution Spec- pp; submitted to Review of Scientiﬁ c troscopic Diagnostic for Divertor and Instruments. Scrape-off Layer Neutral and Impurity Emission Measurements in the National Staack, D., Raitses, Y., and Fisch, Spherical Torus Experiment,” Rev. Sci. N.J., “Reducing Plasma Perturbations Instrum. 74 (March 2003) 2094-2097. with Segmented Metal Shielding on Presented at the Fourteenth APS Topical Electrostatic Probes,” Princeton Plasma Conference on High Temperature Plasma Physics Laboratory Report PPPL-3752 Diagnostics (8-10 July 2002, Madison, (October 2002) 12 pp; submitted to Wisconsin). Review of Scientiﬁ c Instruments.

†Spaleta, J., Majeski, R., Phillips, C.K., §Startsev, E.A. and Davidson, R.C., Dumont, R.J., Kaita, R., Soukhanovskii, “Electromagnetic Weibel Instability in V., and Zakharov, L., “Investigations of Intense Charged Particle Beams With Low and Moderate Harmonic Fast Wave Large Temperature Anisotropy,” Physics Physics on CDX-U,” AIP Conference of Plasmas 10 (December 2003) 4829- Proceedings 694 (15 December 2003) 4836. 213-218; Princeton Plasma Physics Lab- oratory Report PPPL-3840 (July 2003) Startsev, E.A. and Davidson, R.C., 4 pp. Presented at the 15th AIP Topical “Intense Sheet Beam Stability Properties Conference on Radio Frequency Power in for Uniform Phase Space Density,” in the Plasmas (19-21 May 2003, Grand Teton Proceedings of the 2003 Particle Accelerator National Park, Moran, Wyoming). Conference (PAC2003) 5 (12-16 May 2003, Portland, Oregon) 2978-2980. *Spong, D.A., Hirshman, S.P. Strickler, D.J., Lyon, J.F., Berry, A., Mikkelsen, Startsev, E.A., and Davidson, R.C., D., Monticello, D., and Ware, A.S., “Kinetic Analysis of Intense Sheet “Conﬁ nement Physics of Quasi-poloidal Beam Stability Properties for Uniform Stellarators,” in the Proceedings of the Phase-space Density,” Phys. Rev. ST 30th European Physical Society Conference Accel. Beams 6 (April 2003) Article No. on Controlled Fusion and Plasma Physics 044401.

193 Startsev, E.A., Davidson, R.C., and Qin, Devices (PSI-15) (27-31 May 2002, Gifu, H., “Analytical Theory and Nonlinear Japan). Delta-f Perturbative Simulations of Tem- perature Anisotropy Instability of Intense *Strait, E.J., Bialek, J., Chance, M.S., Charged Particle Beams,” Phys. Rev. ST Chu. M.S., Edgell, D.H., Ferron, J.R., Accel. Beams 6 (August 2003) Article Greenﬁ eld, C.M., Garofalo, A.M., No. 084401 (15 pages). Humphreys, D.A., Jackson, G.L., Jay- kumar, R.J., Jernigan, T.C., Kim, J.S., Startsev, E.A., Davidson, R.C., and Qin, LaHaye, R.J., Lao, L.L., Luce, T.C., H., “Kinetic Studies of Temperature Ani- Makowski, M.A., Murakami, M., sotropy Instability in Intense Charged Par- Navratil, G.A., Okabayashi, M., Petty, ticle Beams,” in the Proceedings of the 2003 C.C., Reimerdes, H., Scoville, J.T., Particle Accelerator Conference (PAC2003) Turnbull, A.D., Wade, M.R., Walker, 5 (12-16 May 2003, Portland, Oregon) M.L., Whyte, D.G., and the DIII-D 3123-3125. Team, “Control of MHD Stability in DIII-D Advanced Tokamak Discharges,” Startsev, Edward A.; Davidson, Ronald “Control of MHD Stability in DIII-D C.; and Qin, Hong, “Nonlinear Delta- Advanced Tokamak Discharges, “in the f Simulation Studies of Intense Charged Proceedings of the 30th European Physical Particle Beams with Large Temperature Society Conference on Controlled Fusion Anisotropy,” Laser and Particle Beams 20 and Plasma Physics (7-11 July 2003, (October 2002) 585-588. St. Petersburg, Russia), Europhysics Conference Abstracts 27A (European Stotler, D.P., D’Ippolito, D.A., LeBlanc, B., Physical Society, 2003) paper O-3.6A. Maqueda, R.J., Myra, J.R., Sabbagh, S.A., This conference proceedings is published and Zweben S.J., “Three-Dimensional on CD-ROM. Papers available in PDF Neutral Transport Simulations of Gas format at http://eps2003.ioffe.ru/ (as of Puff Imaging Experiments,” Princeton 12 November 2003). Plasma Physics Laboratory Report PPPL- 3875 (September 2003) 6 pp. Presented Stratton, B.C., Hawkes, N.C., Huysmans, at the 9th International Workshop on G.T.A., Breslau, J.A., Zakharov, L.E., Plasma Edge Theory in Fusion Devices (3-5 Alper, B., Budny, R.V., Challis, C.D., September 2003, San Diego, California); Deangelis, R., Drozdov, V., Fenzi, C., conference proceedings to be published in Giroud, C., Hender, T.C., Hobirk, J., Contributions to Plasma Physics. Jardin, S.C., Joffrin, E., Lomas, P.J., Lotte, P., Mailloux, J., Park, W., Rachlew, Stotler, D.P., LaBombard, B., Terry, J.L., E., Reyes-Cortes, S., Solano, E., Tala, and Zweben, S.J., “Neutral Transport T., Zastrow, K-D., and JET-EFDA of Simulations of Gas Puff Imaging Contributors, “Equilibria and Stability of Experiments,” J. Nucl. Mater. 313-316 JET Discharges with Zero Core Current (March 2003) 1066-1070; Princeton Density,” Princeton Plasma Physics Plasma Physics Laboratory Report PPPL- Laboratory Report PPPL-3756 (October 3705 (June 2002) 10 pp. Presented at the 2002) 5 pp. Presented at the Nineteenth 15th International Conference on Plasma IAEA Fusion Energy Conference (14-19 Surface Interactions in Controlled Fusion October 2002, Lyon, France).

194 Stratton, B.C., Johnson, D., Feder, *Swain, D.W., Carter, M.D., Wilson, J.R., R., Fredrickson, E., Neilson, H., Ta ka- Ryan, P.M., Wilgen, J.B., Hosea, J., and ha shi, H., Zarnstorff, M., Cole, M., Rosenberg, A., “Loading and Asymmetry Goranson, P., Lazarus, E., and Nelson, Measurements and Modeling for the B., “Diagnostics for the National Com- National Spherical Torus Experiment pact Stellarator Experiment,” in the Ion Cyclotron Range of Frequencies Proceedings of the 14th International System,” Fusion Sci. Technol. 43 (June Stellarator Workshop (22-26 September 2003) 503. 2003, Greifswald, Germany) P.We25; Proceedings to be published on a CD- Synakowski, E.J., Bell, M.G., Bell, R.E., ROM. Papers available at http://www. Bigelow, T., Bitter, M., Blanchard, W., ipp.mpg.de/eng/for/veranstaltungen/ Boedo, J., Bourdelle, C., Bush, C., Darrow, workshops/stellarator_2003/SWS- D.S., Efthimion, P.C., Fredrickson, E.D., CDROM/papers/papers_alphabetic. Gates, D.A., Gilmore, M., Grisham, html (as of 15 May 2004). Princeton L.R., Hosea, J.C., Johnson, D.W., Kaita, Plasma Physics Laboratory Report PPPL- R., Kaye, S.M., Kubota, S., Kugel, H.W., 3872 (September 2003) 6 pp. LeBlanc, B.P., Lee, K., Maingi, R., Manickam, J., Maqueda, R., Mazzucato, *Stutman, D., Finkenthal, M., Bell, E., Medley, S.S., Menard, J., Mueller, D., M.G., Bell, R.E., Bourdelle, C., Kaye, Nelson, B.A., Neumeyer, C., Ono, M., S.M., LeBlanc, B.P., Menard, J.E., Paoletti, F., Park, H.K., Paul, S.F., Peng, Soukhanovskii, V., Synakowski, E.J., and Y.-K.M., Phillips, C.K., Ramakrishnan, the NSTX Team, “Correlation between S., Raman, R., Roquemore, A.L., Impurity Transport and Toroidal Rotation Rosenberg, A., Ryan, P.M., Sabbagh, in NSTX,” in the Proceedings of the 30th S.A., Skinner, C.H., Soukhanovskii, European Physical Society Conference on V., Stevenson, T., Stutman, D., Swain, Controlled Fusion and Plasma Physics (7- D.W., Taylor, G., Von Halle, A., Wilgen, 11 July 2003, St. Petersburg, Russia), J., Williams, M., Wilson, J.R., Xu, X., Europhysics Conference Abstracts 27A Zweben, S.J., Akers, R., Barry, R.E., (European Physical Society, 2003) paper Beiersdorfer, P., Bialek, J.M., Blagojevic, P-3.100. This conference proceedings is B., Bonoli, P.T., Budny, R., Carter, published on CD-ROM. Papers available M.D., Chrzanowski, J., Davis, W., Deng, in PDF format at http://eps2003.ioffe. B., Doyle, E.J., Dudek, L., Egedal, J., ru/ (as of 12 November 2003). Ellis, R., Ferron, J.R., Finkenthal, M., Foley, J., Fredd, E., Glasser, A., Gibney, *Stutman, D., Finkenthal, M., Moos, T., Goldston, R.J., Harvey, R., Hatcher, H.W., Fournier, K.B., Kaita, R., Johnson, R.E., Hawryluk, R.J., Heidbrink, W., D., Roquemore, L., “Integrated Impurity Hill, K.W., Houlberg, W., Jarboe, T.R., Diagnostic Package for Magnetic Fusion Jardin, S.C., Ji, H., Kalish, M., Lowrance, Experiments,” Rev. Sci. Instrum. 74 J., Lao, L.L., Lee, K.C., Levinton, F.M., (March 2003) 1982-1987. Presented at Luhmann, N.C., Majeski, R., Marsala, R., the Fourteenth APS Topical Conference on Mastrovito, D., Mau, T.K., McCormack, High Temperature Plasma Diagnostics (8- B., Menon, M.M., Mitarai, O., Nagata, 10 July 2002, Madison, Wisconsin). M., Nishino, N., Okabayashi, M., Oliaro,

195 G., Pacella, D., Parsells, R., Peebles, presented at the Nineteenth IAEA Fusion T., Peneﬂ or, B., Piglowski, D., Pinsker, Energy Conference (14-19 October 2002, R., Porter, G.D., Ram, A.K., Redi, M., Lyon, France). Rensink, M., Rewoldt, G., Robinson, J., Roney, P., Schaffer, M., Shaing, K., *Tanabe, T., Bekris, N., Coad, P., Skinner, Shiraiwa, S., Sichta, P., Stotler, D., C.H., Glugla, M., and Miya, N., “Tritium Stratton, B.C., Takase, Y., Tang, X., Retention of Plasma Facing Components Vero, R., Wampler, W.R., Wurden, G.A., in Tokamaks,” J. Nucl. Mater 313-316 Xu, X.Q., Yang, J.G., Zeng, L., and (March 2003) 478-490. Presented at the Zhu, W., “The National Spherical Torus 15th International Conference on Plasma Experiment (NSTX) Research Program Surface Interactions in Controlled Fusion and Progress Towards High Beta, Long Devices (PSI-15) (27-31 May 2002, Gifu, Pulse Operating Scenarios,” Princeton Japan). Plasma Physics Laboratory Report PPPL- 3758 (October 2002) 12 pp. Presented †Taylor, G., Efthimion, P.C., Jones, at the Nineteenth IAEA Fusion Energy B., Bell, G.L., Bers, A., Bigelow, T.S., Conference (14-19 October 2002, Lyon, Carter, M.D., Harvey, R.W., Ram, A.K., France). Rasmussen, D.A., Smirnov, A.P., Wilgen, J.B., and Wilson, J.R., “Electron Bernstein Takahashi, H., Schaffer, M.J., Wave Research on NSTX and CDX- Fredrickson, E.D., Austin, M.E., Evans, U,” AIP Conference Proceedings 694 T.E., Lao, L.L., and Watkins, J.G., (15 December 2003) 396-402; Prince- “Observation of Current in SOL Plasma ton Plasma Physics Laboratory Report and Possible Roles Played by Associated PPPL-3820 (June 2003) 4 pp. Presented Error Field in AT Discharges in DIII- at the 15th AIP Topical Conference on Tokamak,” in the Proceedings of the 30th Radio Frequency Power in Plasmas (19-21 European Physical Society Conference on May 2003, Grand Teton National Park, Controlled Fusion and Plasma Physics (7- Moran, Wyoming). 11 July 2003, St. Petersburg, Russia), Europhysics Conference Abstracts 27A Taylor, G., Efthimion, P.C., Jones, B., (European Physical Society, 2003) paper LeBlanc, B.P., Wilson, J.R., Wilgen, P-3.178. This conference proceedings is J.B., Bell, G.L., Bigelow, T.S., Maingi, published on CD-ROM. Papers available R., Rasmussen, D.A., Harvey, R.W., in PDF format at http://eps2003.ioffe. Smirnov, A.P., Paoletti, F., and Sabbagh, ru/ (as of 12 November 2003). S.A., “Enhanced Conversion of Thermal Electron Bernstein Waves to the Extra- *§Takenaga, H., Higashijima, S., Oyama, ordinary Electromagnetic Mode on the N., Bruskin, L.G., Koide, Y., Ide, S., National Spherical Torus Experiment Shirai, H., Sakamoto, Y., Suzuki, T., (NSTX)” Phys. Plasmas 10 (May 2003) Hill, K.W., Rewoldt, G., Kramer, G.J., 1395-1401; Princeton Plasma Physics Nazikian, R., Takizuka, T., Fujita, T., Laboratory Report PPPL-3757 (October Sakasai, A., Kamada, Y., Kubo, H., JT- 2002) 25 pp. 60 Team, “Relationship between Particle and Heat Transport in JT-60U Plasmas *Terry, J.L., Zweben, S.J., Hallatschek, with Internal Transport Barrier,” Nucl. K., LaBombard, B., Maqueda, R.J., Fusion 43 (October 2003) 1235-1245; Bai, B., Boswell, C.J., Greenwald, M.,

196 Kopon, D., Nevins, W.M., Pitcher, C.S., H., Usui, K., Honda, A., Guangjiu, L., Rogers, B.N., Stotler, D.P., and Xu, X.Q., Watanabe, K., Inoue, T., Hanada, M., “Observations of the Turbulence in the Kashiwagi, M., Morishita, T., Dairaku, Scrap-off-layer of Alcator C-Mod and M., and Takayanagi, T., Nucl. Fusion 43 Comparisons with Simulation,” Phys. (July 2003) 522-526. Plasmas 10 (May 2003) 1739-1747. *Valovic, M., Budny, R., Garzotti, L., *Tobita, K., Kusama, Y., Shinohara, K., Garget, X., Korotkov, A.A., Rapp, J., Nishitani, T., Kimura, H., Kramer, G.J., Neu, R., Sauter, O., Weisen, H., deVries, Nemoto, M., Kondoh, T. Oikawa, T., P., Alper, B., Beurskens, M., Brzozowski, Morioka, A., Hamamatsu, K., Wang, J., McDonald, D., Leggate, H., Parail, V., S., Takeji, S., Takechi, M., Ishikawa, and JET EFDA contributors, “Density M., Tani, K., Saigusa, M., and Ozeki, Peaking in ELMy H-mode in JET,” in the T., “Energetic Particle Experiments in Proceedings of the 30th European Physical JT-60U and their Implications for a Society Conference on Controlled Fusion Fusion Reactor,” Fusion Sci. Technol. 42 and Plasma Physics (7-11 July 2003, (September-November 2002) 315-326. St. Petersburg, Russia), Europhysics Conference Abstracts 27A (European Trintchouk, F., Yamada, M., Ji, H., Physical Society, 2003) paper P-1.105. Kulsrud, R.M., Carter, T.A., “Mea- This conference proceedings is published surement of the Transverse Spitzer Re- on CD-ROM. Papers available in PDF sis tivity during Collisional Magnetic format at http://eps2003.ioffe.ru/ (as of Reconnection,” Phys. Plasmas 10 (Jan- 12 November 2003). uary 2003) 319-322; Princeton Plasma Physics Laboratory Report PPPL-3750 *Vdovin, V.L., Wesner, F., Hartmann, D., (September 2002) 14 pp. Watari, T., and Monticello, D., “ICRF Plasma Heating in large Stellarators,” Tzenov, S.I. and Davidson, R.C., “Renor- in the Proceedings of the 30th European malization Group Reduction of the Physical Society Conference on Controlled Hénon Map and Application to the Fusion and Plasma Physics (7-11 July Transverse Betatron Motion in Cyclic 2003, St. Petersburg, Russia), Europhysics Accelerators,” New J. Phys. 5 (June 2003) Conference Abstracts 27A (European Article 67. Physical Society, 2003) paper O-4.3B. This conference proceedings is published *Uhm, H.S. and Davidson, R.C., on CD-ROM. Papers available in PDF “Effects of Electron Collisions on the format at http://eps2003.ioffe.ru/ (as of Resistive Hose Instability in Intense 12 November 2003). Charged Particle Beams Propagating through Background Plasma,” Phys. Rev. *Wang, T.-S.F., Channell, P.J., Macek, ST Accel. Beams 6 (March 2003) Article R.J., and Davidson, R.C., “Centroid No. 034204 (10 pages). Theory of Transverse Electron-Proton Two-Stream Instability in a Long Proton *Umeda, N., Grisham, L.R., Yamamoto, Bunch,” Phys. Rev. ST Accel. Beams 6 T., Kuriyama, M., Kawai, M., Ohga, (January 2003) Article No. 014204 (17 T., Mogaki, K., Akino, N., Yamazaki, pages).

197 *Ware, A.S., Westerly, D., Barcikowski, Wong, K.L., Budny, R., Nazikian, R., E., Berry, L.A. Fu, G., Hirshman, S.P., Petty, C.C., Greenfi eld, C.M., Heidbrink, Lyon, J.F., Sanchez, R., Spong, D.A., W.W., and Ruskov, E., “Alpha Channeling and Strickler, D.J., “Second Ballooning Experiment in the DIII-D Tokamak,” Stability Access in the Quasi-poloidal submitted to Physical Review Letters. Stellarator,” in the Proceedings of the 30th European Physical Society Conference on *Yamada, H., Murakami, S., Yamazaki, Controlled Fusion and Plasma Physics (7- K., Kaneko, O., Miyazawa, J., Sakamoto, 11 July 2003, St. Petersburg, Russia), R., Watanabe, K.Y., Narihara, K., Ta- Europhysics Conference Abstracts 27A na ka, K., Sakakibara, S., Osakabe, (European Physical Society, 2003) paper M., Peterson, B.J., Morita, S., Ida, K., P-4.11. This conference proceedings is Inagaki, S., Masuzaki, S., Morisaki, published on CD-ROM. Papers available T., Rewoldt, G., and 71 additional co- in PDF format at http://eps2003.ioffe. authors representing 8 institutions, ru/ (as of 12 November 2003). “Impact of Heat Deposition Profi le on Global Confi nement of NBI Heated *Wheatley, V., Pullin, D.I., and Samtaney, Plas mas in the LHD,” Nucl. Fusion 43 R., “On the Regular Refraction of a MHD (August 2003) 749-755. Shock at an Inclined Planar Density Interface,” submitted to the Journal of *Yamamoto, T., and The JT-60U Team Fluid Mechanics. (including Grisham, L.R.), “Tech nological Development and Progress of White, R. and Zakharov, L.E., “Hamil- Plasma Performance on the JT-60U,” tonian Guiding Center Equations in To- Fusion Eng. Des. 66-68 (September roidal Magnetic Confi gurations,” Phys. 2003) 39-48. Presented at the 22nd Plasmas 10 (March 2003) 573-576; Symposium on Fusion Technology (SOFT Princeton Plasma Physics Laboratory 2002) (9-13 September 2002, Marina Report PPPL-3734 (September 2002) Congress Center, Helsinki, Finland). 10 pp. *Yamamoto, T., Kuriyama, M., Umeda, Wilson, J.R., Bell, R.E., Bernabei, S., N., Lei, G., Grisham, L.R., Kawai, M., Bitter, M., Bonoli, P., Gates, D., Hosea, Ohga, T., and the JT-60U NBI Team, J., LeBlanc, B., Mau, T.K., Medley, Plasma Fusion Research Series 5 (2003) S., Menard, J., Mueller, D., Ono, M., 474-477. Phillips, C.K., Pinsker, R.I., Raman, R., Rosenberg, A., Ryan, P., Sabbagh, §Yampolsky, N.A., Malkin, V.M., and S., Stutman, D., Swain, D., Takase, Fisch, N.J., “Finite-duration Seeding Y., Wilgen, J., and the NSTX team, Effects in powerful Backward Raman “Exploration of High Harmonic Fast Amplifi ers,” Phys. Rev. E 69 (March Wave Heating on the National Spherical 2004) Article No. 036401; Princeton Torus Experiment,” Phys. Plasmas 10 Plasma Physics Laboratory Report PPPL- (May 2003) 1733-1738; Princeton 3839 (July 2003) 6 pp. Plasma Physics Laboratory Report PPPL- 3785 (February 2003) 26 pp. *Yavorskij, V.A., Darrow, D., Golo- borod’ko, V.Ya., Reznik, S.N.,

198 Holzmueller-Steinacker, U., Gorelenkov, Magnetic Field,” Phys. Rev. Lett. 90 (31 N., and Schoepf, K., “Fast Non-Adi- January 2003) Article 045001; Princeton abaticity in Spherical Tokamaks,” Nucl. Plasma Physics Laboratory Report PPPL- Fusion 42 (October 2002) 1210-1215; 3679 (March 2002) 12 pp. Princeton Plasma Physics Laboratory Re- port PPPL-3733 (August 2002) 22 pp. Zakharov, L.E., “Stabilization of Tokamak Plasma by Lithium Streams,” Young, Kenneth M., “Diagnostics Phys. Plasmas 9 (November 2002) for FIRE: A Status Report,” Rev. Sci. 4591-4595; Princeton Plasma Physics Instrum. 74 (March 2003) 1761-1765; Laboratory Report PPPL-3483 (August Princeton Plasma Physics Laboratory 2000) 8 pp. Report PPPL-3720 (July 2002) 15 pp. Presented at the Fourteenth APS Topical Zakharov, L.E., Gorelenkov, N.N., Conference on High Temperature Plasma White, R.B., Krasheninnikov, S.I., and Diagnostics (8-10 July 2002, Madison, Pereverzev, G.V., “Plasma Physics Regimes Wisconsin). in Tokamaks with Li Walls,” Princeton Physics Laboratory Report PPPL-3856 *Yu, S.S., Anders, A., Eylon, S., (August 2003) 23 pp; submitted to Henestroaza, E., Roy, P., Shuman, D., Fusion Engineering and Design. Waldron, W., Sharp, W., Rose, D., Welch, D., Efthimion, P.C., and Gilson, Zakharov, L.E., Krasheninnikov, S.I., E.P., “Focusing and Neutralization of Galkin, S.A., Parks, P.B., and Fredrickson, Intense Charged Particle Beams,” in the E.D., “Negative Central Current and q0 Proceedings of the 2003 Particle Accelerator Equilibria and Relaxation in Tokamaks,” Conference (PAC2003) 1 (12-16 May in the Proceedings of the 30th European 2003, Portland, Oregon) 98-101. Physical Society Conference on Controlled Fusion and Plasma Physics (7-11 July Zaharia, Sorin and Cheng, C.Z., “3-D 2003, St. Petersburg, Russia), Europhysics Force-balanced Magnetospheric Con ﬁ g- Conference Abstracts 27A (European urations,” Princeton Plasma Physics Lab- Physical Society, 2003) paper P-2.112. oratory Report PPPL-3783 (February This conference proceedings is published 2003) 18 pp; submitted to Annales on CD-ROM. Papers available in PDF Geophysicae. format at http://eps2003.ioffe.ru/ (as of 12 November 2003). Zaharia, Sorin and Cheng, C.Z., “Near-earth Thin Current Sheets and Zatz, Irving J., “TFTR D&D Project: Birkeland Currents during Substorm Final Examination and Testing of the Growth Phase,” Geophys. Res. Lett. 30 TFTR TF-Coils,” Princeton Plasma (4 September 2003) Article No. 1883; Physics Laboratory Report PPPL-3777 Princeton Plasma Physics Laboratory (January 2003) 52 pp. Report PPPL-3809 (April 2003) 5 pp. Zweben, S.J., Kornak, T.W., Majeski, Zakharov, L.E., “Magnetic Propulsion of D., Schilling, G., Skinner, C.H., Wilson, Intense Lithium Streams in a Tokamak R., and Kuzma, N., “Evaluation of Pos-

199 sible Nuclear Magnetic Resonance Diag- §Zweben, S.J., Maqueda, R., Stotler, D.P., nostic Techniques for Tokamak Ex per- Keese, A., Boedo, J., Bush, C., Kaye, S., iments,” Rev. Sci. Instrum. 74 (March LeBlanc, B., Lowrance, J., Mastrocola, 2003) 1460-1464; Princeton Plasma V., Maingi, R., Nishino, N., Renda, G., Physics Laboratory Report PPPL-3734 Swain, D., Wilgen, J., and the NSTX (August 2002) 14 pp. Presented at the Team, “High Speed Imaging of Edge Fourteenth APS Topical Conference on Turbulence in NSTX,” Nucl. Fusion High Temperature Plasma Diagnostics (8- 44 (January 2004) 134-153; Princeton 10 July 2002, Madison, Wisconsin). Plasma Physics Laboratory Report PPPL- 3795 (March 2003) 51 pp.

200 Abbreviations, Acronyms, and Symbols

1-D One-dimensional 2-D Two-dimensional 3-D Three-dimensional

AFOSR (U.S.) Air Force Offi ce of Scientifi c Research Alcator A tokamak at the Plasma Science and Fusion Center C-Mod at the Massachusetts Institute of Technology ALPS (Energy) Advanced Liquid Plasma-facing Surface Program (a U.S. Department of Energy Program) AMP Adaptive Mesh Refi nement AMR Adaptive Mesh Refi nement AMTEX American Textile Partnership APEX Advanced Power Extraction Program (a U.S. Department of Energy Program) ARIES Advanced Reactor Innovation Evaluation Studies ARL Army Research Laboratory ARSC Arctic Region Supercomputing Center AS Advanced Stellarator ASDEX Axially Symmetric Divertor Experiment (at the Max-Planck- Institut für Plasmaphysik, Garching, Germany) AT Advanced Tokamak

Bt Toroidal Magnetic Field BES Beam Emission Spectroscopy BEST Beam Equilibrium Stability and Transport Code BPAC Burning Plasma Assessment Committee (under the National Research Council BPX Burning Plasma Experiment

CAD Computer-aided Design CADD Computer-aided Design and Drafting CAE Compressional Alfvén Eigenmodes CAIP Center for Advanced Information Processing at Rutgers University, New Jersey CCD Charge-coupled Device CD Current Drive

201 CD-2 Critical Decision 2 CDR Conceptual Design Review CDX-U Current Drive Experiment-Upgrade at the Princeton Plasma Physics Laboratory CER Charge-exchange Recombination system on DIII-D at General Atomics in California CFC Carbon Fiber Composite CHE Coaxial Helicity Ejection CHERS Charge-exchange Recombination Spectrometer CHI Coaxial Helicity Injection CIT Compact Ignition Tokamak cm Centimeter C-Mod A tokamak in the “Alcator” family at the Plasma Science and Fusion Center at the Massachusetts Institute of Technology CME Coronal Mass Ejection CPPG Computational Plasma Physics Group at the Princeton Plasma Physics Laboratory CRADAs Cooperative Research and Development Agreements CTF Component Test Facility CY Calendar Year

D-D Deuterium-deuterium D-T Deuterium-tritium D&D Decontamination and Decommissioning DARPA Defense Advanced Research Projects Agency DBM Drift Ballooning Model DE Differential Evolution DIII-D A toka mak at the DIII-D Na tion al Fusion Fa cil i ty at General Atomics in San Diego, California DOE (United States) De part ment of Energy DWC Diamond Wire Cutting

EAEs Ellipticity-induced Alfvén Eigenmodes EBW Electron-Bernstein Wave (Heating) ECCD Electron Cyclotron Cur rent Drive ECE Electron Cyclotron Emis sion ECEI Electron Cyclotron Emission Imaging (Radiometer) ECH Electron Cyclotron Heating ECR Electron Cyclotron Resonance ECRH Electron Cyclotron Res o nance Heating EDA Enhanced Dα Mode EFDA European Fusion De vel op ment Agreement EFIT An equilibrium code E-LHDI Electrostatic Lower-hy brid Drift Instability

202 ELM Edge Localized Modes ELVS Graphics Program EPM Energetic Particle Mode ER/WM Environmental Res to ra tion and Waste Man age ment ERD Edge Rotation Diagnostic ERP Enterprise Resource Plan ning ES&H Environment, Safety, and Health ET Experimental Task ETG Electron-temperature Gradient Mode eV Electron Volt

FAC Field-aligned Current FCC Fusion Computational Center FEAT Fusion Energy Advanced Tokamak FEM Finite Element Method FES Fusion Energy Sciences FESAC Fusion Energy Sciences Advisory Committee FIRE Fusion Ignition Research Experiment (a na tion al design study collaboration) FIReTIP Far-infrared Tangential Interferometer and Polarimeter FLC Federal Laboratory Consortium (for Technology Transfer) FLR Field-line Resonance FPT Fusion Physics and Technology, Inc. FRC Field-reversed Conﬁ guration FTP File Transfer Protocol FW Fast Wave FY Fiscal Year

GA General Atomics in San Diego, California GAE Global Alfvén Eigenmodes GDC Glow Discharge Cleaning GEM Gas Electronic Multiplier GFDL Gas Fluid Dynamics Laboratory (on Princeton University’s James Forrestal Campus) GPI Gas Puff Imaging GTC Gyrokinetic Toroidal Code

H-mode High-conﬁ nement Mode HCX High Current Experiment at the Princeton Plasma Physics Laboratory HFS High-ﬁ eld Side HHFW High-harmonic Fast-waves HIT-II Helicity Injected Torus II at the University of Washington, Seattle, Washington

203 HRMIS Human Resources Management Information System HXR Hard X-Ray HYM Hybrid and MHD Code

Ip Plasma Current I/O Input/Output IBX Integrated Beam Experiment ICE Ion Cyclotron Emission ICF Inertial Conﬁ nement Fusion ICRF Ion Cyclotron Range of Frequencies ICW Ion-cyclotron wave IDSP Ion Dynamic Spec trosco py Probe; an optical probe used to measure local ion temperature and ﬂ ows during mag net ic reconnection IGNITOR Ignited Torus IMF Interplanetary Magnetic Field IPP Institut für Plasmaphysik, Garching, Germany IPR Institute for Plasma Research, Gujarat, India IR Infrared IRE Integrated Research Ex per i ment at the Prince ton Plasma Physics Laboratory IRE Internal Reconnection Event ISS International Stellarator Scaling ITB Internal Transport Barrier ITER “The Way” in Latin. Formerly interpreted to stand for International Ther mo nu cle ar Experimental Reactor, although this usage has been discontinued. ITG Ion-temperature Gradient Mode

JAERI Japan Atomic Energy Re search Institute JET Joint European Torus (JET Joint Un der tak ing) in the United Kingdom JET-EP Joint European Torus Enhancement Program JFT-2M A small Japanese tokamak JHU Johns Hopkins University JT-60U Japanese Tokamak at the Japan Atomic Energy Research Institute kA Kiloampere KAM Kolmogorov-Arnold-Mosher KAWs Kinetic Alfvén Waves keV Kiloelectron Volt kG Kilogauss KMB Kinetic Ballooning Mode

204 KSTAR Korea Superconducting Tokamak Advanced Research device being built in Taejon, South Korea kV Kilovolt kW Kilowatt

L-mode Low-conﬁ nement Mode LBNL Lawrence Berkeley National Laboratory LFS Low-ﬁ eld Side LH Lower-hybrid LHCD Lower-hybrid Current Drive LHD Large Helical Device; a stellarator operating in Japan LHDI Lower-hybrid Drift Instability LIF Laser-induced Fluorescence LLNL Lawrence Livermore National Laboratory LPDA Laboratory Program De vel op ment Activities at the Princeton Plasma Physics Laboratory LTX Liquid Tokamak Experiment

MA Megampere MAST Mega Amp Spherical Torus at the Culham Laboratory, United Kingdom MAV Micro Air Vehicle MHD Magnetohydrodynamic MHz Megahertz MINDS Miniature Integrated Nuclear Detector System MIR Microwave Imaging Reﬂ ectometer MIT Massachusetts Institute of Technology in Cam bridge, Massachusetts MLM Multilayer Mirror MNX Magnetic Nozzle Ex per i ment at the Princeton Plasma Physics Laboratory MPP Massively Parallel Processor MPTS Multi-point Thomson Scat ter ing MRX Magnetic Reconnection Experiment at the Prince ton Plasma Phys ics Laboratory ms, msec Millisecond MSE Motional Stark Effect (Di ag nos tic) MW Megawatt

NASA National Aeronautics and Space Administration NBCD Neutral-beam Current Drive NBI Neutral Beam Injection (Heating) NCSX National Compact Stel lar a tor Experiment (a Princeton Plasma Physics Laboratory-Oak Ridge National Laboratory fabrication project)

205 NERSC National Energy Re search Supercomputer Center NIFS National Institute of Fusion Science (Japan) NJTC New Jersey Technology Council NNBI Negative-ion-based Neutral-beam Injection NPA Neutral Particle Analyzer NRC National Research Council NRC Nuclear Regulatory Commission NRL Naval Research Lab o ra to ry NSF National Science Foun da tion NSO Next-step Option NSO-PAC Next-step Option Program Advisory Committee NSST Next-step Spherical Torus NSTX National Spherical Torus Experiment at the Prince ton Plasma Physics Laboratory NTCC National Transport Code Collaboration NTM Neoclassical Tearing Mode NTX Neutralized Transport Experiment NUF (DOE) National Undergraduate Fellowship

OFES Ofﬁ ce of Fusion Energy Sciences (at the U.S. Department of En er gy) OH Ohmic Heating ORNL Oak Ridge National Lab o ra to ry, Oak Ridge, Tennessee ORPA Ofﬁ ce of Research and Project Ad min is tra tion at Princeton University OS Optimized Shear OSHA Occupational Safety and Health Administration

PAC Program Advisory Com mit tee PBX Princeton Beta Experiment, predecessor to PBX-M at the Princeton Plasma Physics Laboratory (no longer operating) PBX-M Princeton Beta Ex per i ment-Modiﬁ cation at the Princeton Plasma Physics Laboratory (no longer operating) PDR Preliminary Design Report PDR Preliminary Design Review PDX Poloidal Divertor Experiment, predecessor to PBX and PBX-M at the Princeton Plasma Physics Laboratory (no longer operating) PF Poloidal Field PFC Plasma-facing Compo nent PICSciE Princeton Institute for Computational Science and Engineering PLT Princeton Large Torus at the Princeton Plasma Physics Laboratory (no longer operating) PPPL Princeton Plasma Physics Laboratory (Princeton University, Prince ton, New Jersey) PPST Program in Plasma Science and Technology

206 PSACI Plasma Science Advanced Scientiﬁ c Computing Initiative PSEL Plasma Science Education Laboratory at the Princeton Plasma Physics Laboratory PSFC Plasma Science and Fusion Center at the Massachusetts Institute of Technology in Cambridge, Massachusetts PTSX Paul Trap Simulator Experiment

Q The ratio of the fusion power produced to the power used to heat a plasma QA Quality Assurance QA Quasi-axisymmetry QAS Quasi-axisymmetry Stel lar a tor QDB Quiescent Double Barrier

R&D Research and Development REs Reconnection Event(s) rf Radio-frequency (Heat ing) RGA Residual Gas Analyzer RI Radiative-improved Con ﬁ nement Mode RMF Rotating Magnetic Field RSAEs Reversed-shear Alfvén Eigenmodes RTAE Resonant TAE RWM Resistive Wall Modes

SBIR Small Business Innovative Research (Program) SciDAC (The Department of Energy Offi ce of Science’s) Scientifi c Discovery through Advance Computing Program SEP Science Education Program SOL Scrape-off Layer SSX Swarthmore Spheromak Experiment located at the Department of Physics and Astronomy, Swarthmore College, Swarthmore, Pennsylvania SSX-FRC Swarthmore Spheromak Experiment-Field-reversed Confi guration ST Spherical Torus START Small Tight Aspect Ratio Tokamak at Culham, United Kingdom STTR Small Business Technology Transfer (Program) SULI (DOE) Science Undergraduate Laboratory Internship SXR Soft X-ray

T Temperature TAE Toroidicity-induced Alfvén Eigenmode or Toroidal Alfvén Eigenmode TEM Trapped-electron Mode TEXTOR Tokamak Experiment for Technologically Ori ent ed Research in Jülich, Germany

207 TF Toroidal Field TFC Topical Computing Facility TFTR Tokamak Fusion Test Re ac tor (1982-1997), at the Princeton Plasma Physics Laboratory (no longer operating) TJ-II A “ﬂ exible” Heliac (stellarator) located at the CIEMAT Institute in Madrid, Spain Tore Supra Tokamak at Cadarache, France TRACE Transition Region and Coronal Explorer (satellite) TSC Transport Simulation Code TWC Tandem Wing Clapper

UC Davis University of California at Davis UCLA University of California at Los Angeles UCSD University of California at San Diego UKAEA United Kingdom Atomic Energy Agency ULF Ultra-low Frequency USDA United States De part ment of Agriculture USDOE United States De part ment of Energy UV Ultraviolet

W7-AS Wendelstein-7 Advanced Stellarator, an op er at ing stellarator in Germa ny W7-X A stellarator being built in Germany WFOs Work For Others WVU West Virginia University

XP Experimental Proposal

Y2K Year 2000

208 June 2004

Editors: Carol A. Phillips and Anthony R. DeMeo

Contributors: J.W. Anderson, M. Bitter, C.Z. Cheng, S.A. Cohen, R.C. Davidson, A.R. DeMeo, P. Efthimion, N.J. Fisch, R.J. Goldston, L.R. Grisham, R.J. Hawryluk, M.T. Iseicz, S. Jardin, H. Ji, D.W. Johnson, S.M. Kaye, A. Kuritsyn, D.V. Lawson, J. Levine, R.P. Majeski, D.M. Meade, L.D. Meixler, R. Nazikian, G.H. Neilson, M. Ono, Y.-M. Peng, C.A. Phillips, A. Post-Zwicker, H. Qin, G. Rewoldt, B. Sarfaty, N.R. Sauthoff, G. Schilling, W.M. Tang, P. Wieser, M.D. Williams, M. Yamada

Cover Design: Gregory J. Czechowicz

Report Design: Carol A. Phillips

Photography: Elle Starkman

Graphics: Gregory J. Czechowicz

Layout: Gregory J. Czechowicz and Carol A. Phillips

The Princeton Plasma Physics Laboratory is funded by the U.S. Department of Energy under contract DE-AC02-76CH03073 and managed by Princeton University.

This report was prepared as an account of work sponsored by the United States Government. Neither the United States nor the United States Department of Energy nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, expressed or implied, or assumes any legal liability, or responsibility for the accuracy, complete- ness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights.

For additional information contact: Information Services Princeton Plasma Physics Laboratory P.O. Box 451 Princeton, NJ 08543 Phone: (609) 243-2750 Fax: (609) 243-2751 e-mail: [email protected] Internet Address: http://www.pppl.gov/