Fluid, kinetic, and electromagnetic effects on rippling instabilities in tokamaks
Tokamak plasmas are unstable against small perturbations that convect resistivity across the confining magnetic field, B vector. The rippling instability is due to the presence of a current along B vector, and a resistivity gradient across B vector. In this thesis the impact on the rippling instability of electron and ion diamagnetic drifts, electron parallel heat conductivity, and electron viscosity is considered. Electromagnetic effects are accounted for, albiet approximately, by means of a vector potential, A vector in parallel with B vector. The linear, normal mode stability calculations are carried out for a plasma slab in a sheared magnetic field. It is found that when the electron temperature, T/sub e/, is low, the rippling mode is unstable and becomes more so as T/sub e/ decreases. For T/sub e/ large, the mode is stable and tends toward marginal stability. This latter trend is overridden by viscosity. Stabilization is due to heat conduction, and stability is enhanced by ion FLR effects. The general conclusion is that the rippling mode is essentially electrostatic, and poses no threat to confinement save at the edge of tokamaks where T/sub e/ is fairly low.
- Research Organization:
- Wisconsin Univ., Madison (USA)
- OSTI ID:
- 7163589
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
700107* -- Fusion Energy-- Plasma Research-- Instabilities
CLOSED PLASMA DEVICES
ELECTROMAGNETIC FIELDS
ELECTRON DRIFT
ELECTRON TEMPERATURE
INSTABILITY
ION DRIFT
PHYSICAL PROPERTIES
PLASMA INSTABILITY
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
VISCOSITY