Marginal Stability Boundaries for Infinite-n Ballooning Modes in a Quasi-axisymmetric Stellarator

Hudson, S.R. ; Hegna, C.C.

Princeton University. Plasma Physics Laboratory.

关键词: Equilibrium Ballooning Instabilities;    Ballooning Instabilities;    Equilibrium -- Mhd Toroidal;    75 Condensed Matter Physics, Superconductivity And Superfluidity;    70 Plasma Physics And Fusion Technology;   

DOI  :  10.2172/815099
RP-ID  :  PPPL-3871
RP-ID  :  AC02-76CH03073
RP-ID  :  815099

美国|英语

来源: UNT Digital Library

【 摘 要 】

A method for computing the ideal-MHD stability boundaries in three-dimensional equilibria is employed. Following Hegna and Nakajima [Phys. Plasmas 5 (May 1998) 1336], a two-dimensional family of equilibria are constructed by perturbing the pressure and rotational-transform profiles in the vicinity of a flux surface for a given stellarator equilibrium. The perturbations are constrained to preserve the magnetohydrodynamic equilibrium condition. For each perturbed equilibrium, the infinite-n ballooning stability is calculated. Marginal stability diagrams are thus constructed that are analogous to (s; a) diagrams for axisymmetric configurations. A quasi-axisymmetric stellarator is considered. Calculations of stability boundaries generally show regions of instability can occur for either sign of the average magnetic shear. Additionally, regions of second-stability are present.