Localized Ballooning Modes in Compact Quasiaxially Symmetric Stellarators

Redi, M.H. ; Canik, J. ; Dewar, R.L. ; Fredrickson, E.D. ; Cooper, W.A. ; Johnson, J.L. ; Klasky, S.

Princeton University. Plasma Physics Laboratory.

关键词: Magnetic Fields;    70 Plasma Physics And Fusion Technology;    Tftr Tokamak;    Stellarators;    Ballooning Instability;   

DOI  :  10.2172/786576
RP-ID  :  PPPL-3578
RP-ID  :  AC02-76CH03073
RP-ID  :  786576

美国|英语

来源: UNT Digital Library

【 摘 要 】

Understanding of ballooning mode stability boundaries may lead to performance improvement of toroidal devices through control of plasma disruptions. Toroidally localized ballooning modes have been found as precursors to high-beta plasma disruptions on the Tokamak Fusion Test Reactor (TFTR) arising in conditions of n=1 kink mode asymmetry. Recent optimization has shown that magnetohydrodynamic (MHD) stability as well as good particle confinement are likely to be achievable in the National Compact Stellarator Experiment (NCSX), a compact, quasiaxially symmetric stellarator (QAS) for values of the plasma near beta = 4%. The configuration, with a major radius of 1.42 m, an aspect ratio of 4.4, a toroidal magnetic field 1.2-1.7 T and 6 MW of neutral-beam heating, is stable to MHD instabilities, and is expected to be limited by high-n kink and ballooning modes. This paper describes the ballooning eigenvalue isosurfaces for NCSX, the first step in an examination of the kinetic stabilization of the ballooning beta limit using a hybrid WKB approach.