Compressibility effects on ideal and kinetic ballooning modes and elimination of finite Larmor radius stabilization
The dynamics of ideal and kinetic ballooning modes are considered analytically including parallel ion dynamics, but without electron dissipation. For ideal modes and typical tokamak parameters, parallel dynamics predominantly determine the growth rate when ..beta.. is within --20%--40% of the ideal threshold, resulting in a substantial reduction in growth rate. Compressibility also eliminates the stabilization effects of finite Larmor radius (FLR); FLR effects (when temperature gradients are neglected) can even increase the growth rate above the magnetohydrodynamic (MHD) value. Temperature gradients accentuate this by adding a new source of free energy independent of the MHD drive, in the region of ballooning coordinate corresponding in MHD to the continuum. Analytic dispersion relations are derived demonstrating the effects above; the formalism emphasizes the similarities between the ideal MHD and kinetic cases.
- Research Organization:
- Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712
- OSTI ID:
- 5309658
- Journal Information:
- Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 29:9; ISSN PFLDA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
700107 -- Fusion Energy-- Plasma Research-- Instabilities
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
ANALYTICAL SOLUTION
BALLOONING INSTABILITY
BETA RATIO
COMPRESSIBILITY
DISPERSION RELATIONS
DYNAMICS
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
ION DRIFT
MAGNETOHYDRODYNAMICS
MECHANICAL PROPERTIES
MECHANICS
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
VARIATIONAL METHODS