The national spherical torus experiment (NSTX) research programme and progress towards high beta, long pulse operating scenarios

Autor:	Manfred Bitter, Vlad Soukhanovskii, E.D. Fredrickson, Roger Raman, R. E. Barry, Richard Majeski, G. Rewoldt, Yueng Kay Martin Peng, M.M. Menon, R. Parsells, T. Stevenson, R. Marsala, Brian Nelson, B. McCormack, E. Fredd, L.L. Lao, P. C. Efthimion, S.A. Sabbagh, Hyeon K. Park, Robert Kaita, R. E. Bell, J. Chrzanowski, M. Rensink, E.J. Doyle, Mark D. Carter, B. C. Stratton, R. Vero, K.C. Lee, Ker-Chung Shaing, Rajesh Maingi, Lei Zeng, C.E. Bush, Masayoshi Nagata, Yuichi Takase, J. Foley, William Heidbrink, J.R. Ferron, Stanley Kaye, Masayuki Ono, Peter Beiersdorfer, C.H. Skinner, G.D. Porter, C. K. Phillips, K. C. Lee, J. Manickam, T. K. Mau, E. J. Synakowski, A. von Halle, R. A. Ellis, D. Mastravito, E. Mazzucato, A. Rosenberg, David Gates, J. C. Hosea, T. Peebles, Neville C. Luhmann, G. Oliaro, J.G. Yang, W. Davis, J. Robinson, John B Wilgen, M. Williams, D.W. Swain, B.P. LeBlanc, B. H. Deng, Jonathan Menard, S. Kubota, Xian-Zhu Tang, D. Piglowski, A. L. Roquemore, M.J. Schaffer, C. Neumeyer, Clarisse Bourdelle, Wayne A Houlberg, Mark Gilmore, T.S. Bigelow, Stephen Jardin, L. Dudek, R. Hatcher, W. Blanchard, J.A. Boedo, S. S. Medley, P. Roney, H.W. Kugel, Michael Finkenthal, R. W. Harvey, W. Zhu, D. S. Darrow, D.P. Stotler, X.Q. Xu, K. W. Hill, James R. Wilson, R.J. Hawryluk, Osamu Mitarai, Robert James Goldston, F. Paoletti, G. Taylor, S.F. Paul, G. A. Wurden, Fred Levinton, Hantao Ji, P.M. Ryan, S. Ramakrishnan, P.T. Bonoli, Thomas Jarboe, M. H. Redi, M. Okabayashi, M.G. Bell, Syun'ichi Shiraiwa, D. Mueller, Choong-Seock Chang, D. Pacella, T. Gibney, B. Peneflor, Larry R. Grisham, B. Blagojevic, R.J. Akers, J. Lawrance, P. Sichta, R.I. Pinsker, William R. Wampler, Nobuhiro Nishino, Abhay K. Ram, Ricardo Maqueda, Alan H. Glasser, Stewart Zweben, Jan Egedal, R.V. Budny, Dan Stutman, M. Kalish, David Johnson, J.M. Bialek
Rok vydání:	2003
Předmět:	Physics Nuclear and High Energy Physics Toroid Physics::Plasma Physics Beta (plasma physics) Divertor Magnetic confinement fusion Plasma Atomic physics Electric current Spherical tokamak Condensed Matter Physics Bootstrap current
Zdroj:	Nuclear Fusion. 43:1653-1664
ISSN:	1741-4326 0029-5515
Popis:	A major research goal of the national spherical torus experiment is establishing long-pulse, high beta, high confinement operation and its physics basis. This research has been enabled by facility capabilities developed during 2001 and 2002, including neutral beam (up to 7?MW) and high harmonic fast wave (HHFW) heating (up to 6?MW), toroidal fields up to 6?kG, plasma currents up to 1.5?MA, flexible shape control, and wall preparation techniques. These capabilities have enabled the generation of plasmas with of up to 35%. Normalized beta values often exceed the no-wall limit, and studies suggest that passive wall mode stabilization enables this for H mode plasmas with broad pressure profiles. The viability of long, high bootstrap current fraction operations has been established for ELMing H mode plasmas with toroidal beta values in excess of 15% and sustained for several current relaxation times. Improvements in wall conditioning and fuelling are likely contributing to a reduction in H mode power thresholds. Electron thermal conduction is the dominant thermal loss channel in auxiliary heated plasmas examined thus far. HHFW effectively heats electrons, and its acceleration of fast beam ions has been observed. Evidence for HHFW current drive is obtained by comparision of the loop voltage evolution in plasmas with matched density and temperature profiles but varying phases of launched HHFW waves. Studies of emissions from electron Bernstein waves indicate a density scale length dependence of their transmission across the upper hybrid resonance near the plasma edge that is consistent with theoretical predictions. A peak heat flux to the divertor targets of 10?MW?m?2 has been measured in the H mode, with large asymmetries being observed in the power deposition between the inner and outer strike points. Non-inductive plasma startup studies have focused on coaxial helicity injection. With this technique, toroidal currents up to 400?kA have been driven, and studies to assess flux closure and coupling to other current drive techniques have begun.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::5a125aeec31d4f4813ea6fb851c9a743 https://doi.org/10.1088/0029-5515/43/12/011 Zobrazit plný text záznamu