CHARACTERIZATION OF THE C-2W PLASMA GUNS

International Atomic Energy Agency Nuclear Fusion Nucl. Fusion 57 (2017) 116021 (8pp) https://doi.org/10.1088/1741-4326/aa7d7b
Achievement of eld-reversed con guration plasma sustainment via 10 MW neutral-beam injection on the C-2U device
H. Gota1 , M.W. Binderbauer1, T. Tajima1,2, S. Putvinski1, M. Tuszewski1, S. Dettrick1, E. Garate1, S. Korepanov1, A. Smirnov1, M.C. Thompson1,
E. Trask1, X. Yang1, L. Schmitz1,3, Z. Lin2, A.A. Ivanov4, T. Asai5 , I. Allfrey1, R. Andow1, M. Beall1, N. Bolte1, D.Q. Bui1, M. Cappello1, F. Ceccherini1,
R. Clary1, A.H. Cheung1, K. Conroy1, B.H. Deng1, J. Douglass1,
A. Dunaevsky1, P. Feng1, D. Fulton1, L. Galeotti1, E. Granstedt1,
M. Griswold1, D. Gupta1, S. Gupta1, K. Hubbard1, I. Isakov1, J.S. Kinley1, K. Knapp1, R. Magee1, V. Matvienko1, R. Mendoza1, Y. Mok1, A. Necas1, S. Primavera1, M. Onofri1, D. Osin1, N. Rath1, T. Roche1, J. Romero1,
T. Schindler1, J.H. Schroeder1, L. Sevier1, D. Sheftman1, A. Sibley1,
Y. Song1, L.C. Steinhauer1, T. Valentine1, A.D. Van Drie1, J.K. Walters1, W. Waggoner1, P. Yushmanov1, K. Zhai1 and The TAE Team1
1 Tri Alpha Energy, Inc., PO Box 7010, Rancho Santa Margarita, CA 92688, United States of America
2 Department of Physics and Astronomy, UCI, Irvine, CA 92697, United States of America
3 Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095, United States of America
4 Budker Institute of Nuclear Physics, Novosibirsk, 630090, Russian Federation
5 College of Science and Technology, Nihon University, Tokyo 101-8308, Japan
E-mail: hgota@trialphaenergy.com
Received 15 December 2016, revised 13 June 2017 Accepted for publication 4 July 2017
Published 4 August 2017
Abstract
Tri Alpha Energy’s experimental program has demonstrated reliable eld-reversed con guration (FRC) formation and sustainment, driven by fast ions via high-power neutral-beam (NB) injection. The world’s largest compact-toroid device, C-2U, was upgraded from C-2 with the following key system upgrades: increased total NB input power from ~4 MW (20 keV hydrogen) to 10+ MW (15 keV hydrogen) with tilted injection angle; enhanced edge-biasing capability inside of each
end divertor for boundary/stability control. C-2U experiments with those upgraded systems have successfully demonstrated dramatic improvements in FRC performance and achieved sustainment of advanced beam-driven FRCs with a macroscopically stable and hot plasma state for up to
5+ ms. Plasma diamagnetism in the best discharges has reached record lifetimes of over 11 ms, timescales twice as long as C-2. The C-2U plasma performance, including the sustainment feature, has a strong correlation with NB pulse duration, with the diamagnetism persisting even several milliseconds after NB termination due to the accumulated fast-ion population by NB injection. Power balance analysis shows substantial improvements in equilibrium and transport parameters, whereby electron energy con nement time strongly correlates with electron temperature; i.e. the con nement time in C-2U scales strongly with a positive power of Te.
Keywords: eld-reversed con guration, compact toroid, neutral-beam injection, current drive, plasma sustainment, aneutronic fusion
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