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26th IAEA FEC Summary : EXC, EXS and PPC Y. Kamada, QST Papers: EXC 101, EXS 57, PPC 26 from 40 devices MEDUSA (Costa Rica ): R~0.14m, a~0.1m, GLAST-III (Pakistan): R=0.2m, a=0.1 m ........ JET (EU): R~3m, a~1.2m W7-X, Welcome to EX sessions ! 2 Welcome to EX ! Start New Operation KTX NSTX-U SST-1 University of Science and Ip~1MA H-modes, Upgraded with Plasma Technology of China H98 ≥ 1, βN ~4 ≥ n=1 no-wall limit Facing Components. RFP with weak/no core MHD R=1.4m, a=0.4m Ip=0.5MA (=>1MA) Bt max=0.35T (=>0.7T) 3 Contents 1. Edge Pedestal System 2. Core Transport 3. Core MHD Stability 4. Operation & Control * Disruption Mitigation is treated in the next talk by Dr. D. Hill 4 H-mode Pedestal Structure and Dynamics Shafranov Shift Fast particles Core Pedestal Plasma Shape (κ, δ, A) ~ Δ B field (3D): RMP plasma response impurity small/no ELM (T, n) (T, regimes Height mitigation Pressure ELM Grassy ELM minor radius Width EDA H-mode EHO, I-mode Turbulence WCM, QCM QH-mode ! Flow Stochasticity Diffusion Heat & Particle Pinch to Divertor grad-p: ELM = Peeling-Ballooning modes (PBMs) width: small-scale turbulence( KBM...) 5 Pressure Gradient ~ Peeling Ballooning Mode Shafranov shift stabilizes COMPASS:The the pedestal gradient, experimental data are in agreement JET and JT-60U: with the EPED confirmed in a wide space model. (EXP6-35, of (κ,δ). Low κ high δ gives lower grad-p, but Komm) COMPASS wider pedestal width, then grassy ELM & good confinement. MHD simulations reproduce (EX/3-4, Urano ) experiment very well. JT-60U and JET: MINERVA-DI: Rotation can destabilize PBMs due to TCV, MAST and TCV minimizing the �∗� effect => JET :The pedestal better fit to exp. data. height has been (TH8-1, Aiba) significantly Multi-machine: JOREK increased by early JET simulations at low increase of βp-core. resistivity/viscosity (EX3-6, Chapman) reproduce experiment (TH8-2, Pamela) 6 ELM crash new key findings KSTAR: Three-stage evolution of ELM Pegasus: J-edge across single was identified using a 2D imaging: (1) ELMs shows the nonlinear quasi-steady filamentary mode with long generation and expulsion of life time n=4-15, (2) abrupt structural current-carrying filaments. transformation into filaments with (EXP4-51, Bongard) irregular poloidal spacing near the onset of crash, (3) and multiple filament bursts during the crash. (EX10-3, Yun) 7 Pedestal evolution during the ELM cycle JET: Pedestal evolution during the ELM cycle: ASDEX-U: 70µs resolution Ti (r) not always consistent with EPED (EX3-3, Maggi) measurement: At ELM, heat flux is Low D2 Gas: first increased at the separatrix, then low-βN: Gradient increases and width constant: Ti(r) becomes flatter. χi comes back not consistent with KBM constraint soon to its pre-ELM neoclassical level . (EXP6-30, Viezzer) Is J-edge expelled by an ELM crash? ? 8 Pedestal Width: key = ne(r) relative to Te,i (r) ASDEX-U: D fueling shifts density profile JET: Pedestal stability improves with outward , and T profile anchored at separatrix reduced radial shift. JET-ILW tends to => causes a significant degradation of the have larger relative shift than JET-C. pedestal top pressure. (EX3-5, Dunne) (EXP6-13, Giroud) Te ped p ne 19 -3 ne,sep(10 m ) pe 9 L-H Transition Threshold Power DIII-D: Dual Mode Nature of JET: Isotope Effect: Non- Pegasus: Ultralow-A Edge Turbulence May linear mass dependence on At low A(~1.2), PLH >> ITPA Explain Isotope and Density L-H power threshold scaling by one order of Scaling of L-H Power (EX5-2,Hillesheim) magnitude.(OV5-4, Fonck) Threshold (EX5-1, Yan) PD, Nunes) Pegasus NSTX MAST Threshold Power KSTAR: PLH increases with (d) (a)(e) (b)(f) (c) δB for any cases with n=1, Ion mode n=2 or mixed-n. (EXP4-4) Ion mode Electron Electron mode Electron Electron Electron mode mode mode mode Ion mode n ~1.5x1019m-3 n ~1.5x10199m-3-3 n ~4.2x1019 9m-3 -3 n ~5x109m-3 e ne~4.2x10e m nee~5x10 m e 10 L-H transition: Behavior of turbulence JET: Radial wavelength of DIII-D: The main-ion poloidal Stationary Zonal Flows scales flow acceleration is quantitatively with the radial correlation consistent with Reynolds-stress- length of turbulence, driven shear flow amplification ~ several times smaller ( EXP3-11, Schmitz) than the width of the edge radial electric field well. (EX5-2, Hillesheim) NSTX: The energy exchange between flows and turbulence was analyzed using GPI .The edge fluctuation do not vary just prior to the H-transition. => Turbulence depletion is probably not the mechanism of the L-H transition in NSTX. (EX5-3, Diallo) ASDEX-U: L-I Transition: Negligible contributions of ZFs. (EXP6-29, Putterich) 11 ELM-free regimes : extended remarkably I-mode QH-mode Alcator C-mod : DIII-D: Discovered Stationary High energy confinement with Temperature pedestal, Quiescent H-mode with Zero Net L-mode Density pedestal, Small impurity, Stationary NBI Torque in double-null shaped and ELM-free. Extended to full field 8T and current plasmas, characterized by 1.7MA. Confirms weak L-I threshold dep. on B, and increased pedestal height & width: wide power range at high B. (EX3-1, Hubbard) sustained for 12τE with excellent confinement (H98y2 ~ 1.5, �N ~ 2). 7.8 T ,1.35 MA (EX3-2, Chen) decreased H =1 98 edge ExB T =7.3keV e0 shear enables destabilization <p>=1.4 atm of broadband turbulence 12 Pedestal fluctuations : variety of interplay EAST: A new stationary small/no KSTAR: Broadband HL-2A: EM turbulence was ELM H-mode was found at low turbulence induced by RMP excited by locally- ��∗ < 0.5, H98 ≳ 1.1, exhibiting a damps the ELM amplitude accumulated impurities. low-n electro-Magnetic Coherent (EXP4-15, Lee) Double critical gradients of Mode. It appears at the low impurity density were frequency boundary of TAE gap. observed and reproduced (+ ELM pacing)(EX10-2, Xu) by theoretical simulation. (OV4-4, Duan) HL-2A: Synchronization of GAMs and magnetic fluctuations was observed in the edge plasmas. (EXP7-27, Yan) 13 Remaining Issue: How is the Pedestal Width determined ? ? (T, n) (T, Pressure ? When pedestal grad-p is below Peeling-Ballooning limit, how does the pedestal width evolve and saturate ? During the ELM cycle? Controllable? 14 Success of RMP ELM Suppression = Phase and Shape DIII-D: ELM control requires KSTAR: Optimal phasing for ASDEX + DIII-D: ELM the applied field to couple to n=1 RMP is consistent with Suppression was obtained an edge stable MHD mode, an ideal plasma response for the first time in AUG at directly observed on high field modeling.(EX1-3, In) low ν* with a plasma shape side. The response is matched to DIII-D (δ~0.3) inversely proportional to ν*. showing the importance of (EX1-2, Paz-Soldan) stable edge kink response. (AUG : EXP6-25, Willensdorfer (PD, Nazikian) MAST: peeling, OV5-3, Kirk ) EAST: n=1 RMP, Plasma response behaves a nonlinear transition from mitigation to suppression of the ELMs (EXP7-4, Sun) 15 Long Pulse ELM Suppression by RMP: Big Progress DIII-D: Fully Noninductive plasmas KSTAR: n=1 RMP ELM suppression was sustained for with high � (≤ 2.8%) and high more than ~90 τE (H89=1.5), and also confirmed to be confinement (H≤ 1.4) sustained for compatible with rotating RMP, wide q95 (4.75 – 5.25) ≤ 2 current relaxation with ECCD (EX1-3, In), (PD, Jeon) and NBCD, and integrated with ELM suppression by n=3 RMP; the EAST: n=1 RMP ELM suppression in long-pulse (> 20s) strong resonant interaction allows was realized with small effect on plasma performance ELM suppression over a wide (H98>1) (P7-4, Sun) range of q95 (EX4-1, Petty) DIII-D KSTAR EAST 16 Core Plasma Transport issues for ITER & DEMO Te/Ti ~ 1 ( <= electron heating (α, high energy NB, IC, ECH), high ne) Electron Transport Small rotation due to small external torque ( => intrinsic torque ) Small central fueling ( high energy NB) => density profile ? Confinement performance with metal divertor can be recovered? Accumulation of heavy impurity (metal wall) ? Isotope Effects on Confinement? 17 Thermal Transport at high Te/Ti DIII-D and JT-60U: Positive Shear (PS) shows JET: High Te/Ti plasmas: Electron reduction in Ti when ECH is added. Negative transport evaluated with linear Central Shear (NCS) minimizes confinement gyro-kinetic simulations GENE: degradation even with increasing Te/Ti~1. DIII- most consistent with D shows smaller rise in low-k turbulent ( ITG/TEM) + ETG. fluctuations in NCS than PS. (EX8-1, Yoshida) => Multi-scale non-linear gyro- DIII-D / JT-60U kinetic simulation underway. (EXP6-14, Mantica) /Ti} /Ti} Te Te T /T ~1 {Low e i {High i i χ χ qegB DIII-D magnec shear Fluctuaon /Ti} /Ti} Te Te PS {Low {High ñ ñ NCS Σ Σ R/LTe 18 Electron thermal Transport NSTX: Electrostatic low-k Gyrokinetic W-7X: Te profile shape follows the ECRH Simulation (GTS) explains ion thermal Power deposition transport , but is not able to explain electron -> no indication of profile stiffness transport. => high-k ETG / EM is important for (EX4-5, Hirsch) electron transport. Nonlinear GYRO simulation explains grad-n stabilization of ETG, but not enough => EM? (EXP4-35, Ren) electron MST: Drift wave turbulence MAST: Fluctuation (TEM) emerges in RFP measured at the top of plasmas when global pedestal is consistent tearing instability is with Electron transport reduced by PPCD. evaluated with linear (EXP5-17, Brower) gyro-kinetic simulations GENE: consistent with ETG.
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    Imaging and Probe Techniques for Wave Dispersion Estimates in Magnetized Plasmas by A. D. Light B.A./B.S., Case Western Reserve University, 2005 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Physics 2013 This thesis entitled: Imaging and Probe Techniques for Wave Dispersion Estimates in Magnetized Plasmas written by A. D. Light has been approved for the Department of Physics Prof. Tobin Munsat Prof. Martin Goldman Date The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. Light, A. D. (Ph.D., Physics) Imaging and Probe Techniques for Wave Dispersion Estimates in Magnetized Plasmas Thesis directed by Prof. Tobin Munsat Fluctuations in magnetized laboratory plasmas are ubiquitous and complex. In addition to deleterious effects, like increasing heat and particle transport in magnetic fusion energy devices, fluctuations also provide a diagnostic opportunity. Identification of a fluctuation with a particular wave or instability gives detailed information about the properties of the underlying plasma. In this work, diagnostics and spectral analysis techniques for fluctuations are developed and applied to two different laboratory plasma experiments. The first part of this dissertation discusses imaging measurements of coherent waves in the Controlled Shear Decorrelation Experiment (CSDX) at the University of California, San Diego. Visible light from ArII line emission is collected at high frame rates using an intensified digital camera.
  • GLAST Science Glossary (PDF)

    GLAST Science Glossary (PDF)

    GLAST SCIENCE GLOSSARY Source: http://glast.sonoma.edu/science/gru/glossary.html Accretion — The process whereby a compact object such as a black hole or neutron star captures matter from a normal star or diffuse cloud. Active galactic nuclei (AGN) — The central region of some galaxies that appears as an extremely luminous point-like source of radiation. They are powered by supermassive black holes accreting nearby matter. Annihilation — The process whereby a particle and its antimatter counterpart interact, converting their mass into energy according to Einstein’s famous formula E = mc2. For example, the annihilation of an electron and positron results in the emission of two gamma-ray photons, each with an energy of 511 keV. Anticoincidence Detector — A system on a gamma-ray observatory that triggers when it detects an incoming charged particle (cosmic ray) so that the telescope will not mistake it for a gamma ray. Antimatter — A form of matter identical to atomic matter, but with the opposite electric charge. Arcminute — One-sixtieth of a degree on the sky. Like latitude and longitude on Earth's surface, we measure positions on the sky in angles. A semicircle that extends up across the sky from the eastern horizon to the western horizon is 180 degrees. One degree, therefore, is not a very big angle. An arcminute is an even smaller angle, 1/60 as large as a degree. The Moon and Sun are each about half a degree across, or about 30 arcminutes. If you take a sharp pencil and hold it at arm's length, then the point of that pencil as seen from your eye is about 3 arcminutes across.