0.x-46 October 1, 1993 ANNUAL to REPORT September 30, 1994 Princeton Plasma Physics Laboratory • . I ILL, . - 8.' ^*"„ " . *' * "IS* • •"•0*k' * r ml! ^fes^ ^M^ PPPL - Q - 52 DISTRIBUTION Of THIS BOSOMED % V** ^ Cover: From top left in clockwise direction: (a) The Tokamak Fusion Test Reactor—TFTR. (b) Scientists in the TFTR Control Room on December 9, 1993, as they waited for data from the first deuterium-tritium experiments to appear on computer monitors. (c) A collage of newspaper headlines heralding the first U.S. deuterium-tritium experiments in TFTR. (d) Inside the TFTR vacuum vessel. (e) PPPL Principal Research Physicist Russell Hulse receiving the 1993 Nobel Prize for Physics from the King of Sweden. (f) A deuterium-tritium plasma in TFTR. Cover Design: Gregory Czechowicz Funding for the color cover was provided by nonappropriated funds. No Department of Energy funds were used. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document Annual Report Covering the Period October 1,1993 to September 30,1994 Princeton University Plasma Physics Laboratory Princeton, New Jersey 08543 PPPL-Q-52 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsi• bility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refer• ence herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom• mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Unless otherwise designated, the work in this report is funded by the United States Department of Energy under contract DE-AC02-76-CHO-3073. Printed in the United States of America DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED Table of Contents Preface iii Awards and Honors „ vii Principal Parameters of Experimental Devices for Fiscal Year 1994 xi Tokamak Fusion Test Reactor 1 Princeton Beta Experiment-Modification 69 Current Drive Experiment-Upgrade 81 Tokamak Physics Experiment 87 International Thermonuclear Experimental Reactor 101 Collaborations 107 Low-Temperature Plasma Research 115 Electron Diffusion Gauge Experiments 119 Theoretical Studies 121 Divertor Modeling ,. 139 High-Field Magnet Project 143 Engineering and Technology Development Department 145 TFTR Shutdown and Removal 161 Technology Transfer 165 Environment, Safety, and Health and Quality Assurance 171 Office of Human Resources and Administration 181 Invention Disclosures for Fiscal Year 1994 189 Office of Resource Management 191 Graduate Education: Plasma Physics 197 Graduate Education: Program in Plasma Science and Technology 201 Science Education Program 203 Section Coordinators 207 Princeton Plasma Physics Laboratory Reports for Fiscal Year 1994 209 Glossary of Abbreviations, Acronyms, Symbols 215 Princeton Plasma Physics Laboratory Fiscal Year 1994 Annual Report —iiiH^BHa^>^ai^i^Mi^B / Preface The Tokamak Fusion Test Reactor (TFTR) project Reactor (ITER); (ii) the improvement of confinement is well into the experimental phase of its deuterium- by further optimization of the lithium-pellet wall-con• tritium (D-T) program, with the objective to derive ditioning technique, so that the fusion-triple-product the maximum amount of experimental data on the in quasi-steady conditions has more than doubled to behavior of tokamak plasmas containing a significant 8.3 x 1020 nr3seckeV; (iii) the identification of the population of energetic alpha particles. Since the ini• physical mechanisms responsible for the beta-limit• tial D-T experiments in December, 1993, the opera• ing disruptions in TFTR; (iv) the further elucidation tional performance of the TFTR, as well as the re• of alpha-particle and thermalized helium transport quired tritium-handling and machine maintenance processes in D-T plasmas; and (v) the demonstration procedures in an activated environment, have im• of ICRF heating of D-T plasmas in the minority-3He proved markedly, so that D-T operation has now be• and second-harmonic-tritium modes, and the identi• come essentially routine, while fully conforming with fication of a promising new radio-frequency method all of the safety and environmental requirements. for "mode-conversion current drive (MCCD)." During the D-T phase, the machine and auxiliary-sys• The overall programmatic mission of the Toka• tems parameters have also been increased, most no• mak Physics Experiment (TPX) is to develop the sci• tably the toroidal field (to 5.6 T) and the neutral-beam entific basis for a compact, continuously operating and power (to 40 MW). The radio-frequency power in the economical tokamak fusion reactor. It will do this by ion-cyclotron-range of frequencies (ICRF) has been demonstrating both the physics and technology needed increased to 11 MW. to extend tokamak operation into the steady-state The results from the initial deuterium-tritium ex• regime and advances in fundamental tokamak per• periments in December, 1993, have been confirmed formance parameters on timescales long compared in subsequent D-T operations. Substantially higher with current-relaxation and plasma-wall equilibration ion temperatures are observed in D-T operation com• times. Favorable results from the Tokamak Physics pared with deuterium only, indicating a strongly fa• Experiment (TPX) are essential to further develop• vorable isotopic mass dependence of ion energy trans• ment of an attractive tokamak fusion reactor and will port in the "supershot" confinement regime. Incre• also benefit the operation of the International Ther• ments in electron temperature are also observed, monuclear Experimental Reactor. Key contributions which can be accounted for only partially by the di• will be in the areas of divertor physics and steady- rect electron heating by alpha particles, implying that state operation. some improvement in electron energy confinement Following a successful Conceptual Design Review must also be occurring. The number of escaping al• in March, 1993, the TPX Project began Preliminary pha particles observed on the lost-alpha detectors is (Title 1) Design in October, 1993. Major industrial consistent with classical predictions of "first orbit" loss. contracts for the plasma-facing components, the mag• No fluctuations of the type associated with alpha- net systems, and the vacuum vessel were awarded in driven collective instabilities were observed during FY94, and contracts for systems integration and con• these experiments. struction management are now in the final stages of The further experimental results achieved on award. Also in FY94, the TPX Project successfully TFTR in FY94 have included (i) the production of 10.7 completed a U.S. Department of Energy Management MW of fusion power and 6.5 MJ of fusion energy, with Systems Review to ensure that the management and a central fusion power density exceeding that projected control systems are in place to proceed with a con• for the International Thermonuclear Experimental struction project. The summary conclusions of this Princeton Plasma Physics Laboratory Fiscal Year 1994 Annual Report III Preface review were that the project management roles and ager, and its involvement in Home Team activities, responsibilities are well understood, that a strong in• especially in physics R&D tasks and the physics "ex• dustrial systems integration contractor and a construc• pert groups," has increased significantly. The Labo• tion manager are planned to ensure that all require• ratory continues to provide the Technical Advisory ments are integrated and controlled, and that, overall, Committee Chair. the basic project control functions are in place. A conceptual design study has begun for a Na• As fiscal year 1994 ends, it becomes clear that the tional Spherical Tokamak Experiment (NSTX), using TPX will not receive construction authorization in hardware from the S-l device, to explore the physics FY95. Accordingly, the TPX Project is now working principles of very-low-aspect-ratio tokamak plasmas. on the basis that construction will be authorized in Such "spherical tokamak (ST)" configurations may the FY96 budget, and so the FY96 plan calls for the provide an attractive alternative route to a tokamak start of Detailed Design and the award of the magnet reactor with compact size and modest magnet require• conductor fabrication contract. The schedule described ments (using normal toroidal-field conductors) or to in the Department of Energy TPX Construction Project an attractive volumetric neutron source. The NSTX Data Sheet, which now reflects the baseline FY96 re• is designed to test the special physics issues of con• quest, is consistent with a July, 2001, "first plasma" cern in the very-low-aspect-ratio configuration, includ• date. ing stability at very high beta (approximately 40%), Operation of the Princeton Beta Experiment-Modi• confinement with very high trapped-particle fraction, fication (PBX-M) was suspended in November, 1993, and high-efficiency noninductive current drive (essen• due