Wall stabilization of high beta plasmas in DIII-D
- General Atomics, San Diego, CA (United States)
- Columbia Univ., New York, NY (United States); and others
Detailed analysis of recent high beta discharges in the DIII-D tokamak demonstrates that the resistive vacuum vessel can provide stabilization of low n magnetohydrodynamic (MHD) modes. The experimental beta values reaching up to {beta}{sub T} = 12.6% are more than 30% larger than the maximum stable beta calculated with no wall stabilization. Plasma rotation is essential for stabilization. When the plasma rotation slows sufficiently, unstable modes with the characteristics of the predicted {open_quotes}resistive wall{close_quotes} mode are observed. Through slowing of the plasma rotation between the q = 2 and q = 3 surfaces with the application of a non-axisymmetric field, the authors have determined that the rotation at the outer rational surfaces is most important, and that the critical rotation frequency is of the order of {Omega}/2{pi} = 1 kHz.
- Research Organization:
- General Atomics, San Diego, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114; AC05-84OR21400; W-7405-ENG-48
- OSTI ID:
- 42489
- Report Number(s):
- GA-A-21914; CONF-941101-9; ON: DE95009607; TRN: 95:003551
- Resource Relation:
- Conference: Meeting of the Division of Plasma Physics of the American Physical Society, Minneapolis, MN (United States), 7-11 Nov 1994; Other Information: PBD: Feb 1995
- Country of Publication:
- United States
- Language:
- English
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