Unstable dissipative drift modes in a sheared magnetic field
Collisional, electrostatic drift waves are shown, within the context of a slab geometry with magnetic shear, to be destabilized by a positive electron temperature gradient eta/sub e/=dlnT/sub e//dlnn. The temperature gradient produces a well which localizes the drift eigenmode near the mode rational surfaces and for reasonable magnetic shear, e.g., L/sub n//L/sub s/=0.05, these dissipative drift waves are linearly unstable when the temperature gradient exceeds a threshold of ..nu../sub e/approx. =3. The crucial feature of this analysis is the inclusion of an energy dependent collision model (Lorentz model). Generally, the mode is most unstable for ..nu../sub c//..omega../sub asterisk/approx. =20 and is stable for ..nu../sub c//..omega../sub asterisk/ /sup greater-thangreater-than//sub less-thanless-than/20. We believe this is the first drift mode, driven solely by diamagnetic currents, which is absolutely unstable within the context of a slab model with magnetic shear. Other collisionless and collisional drift modes are found to be stable when the full electron dynamics are included. Finite ..beta.. effects are found to have a strong stabilizing influence on this instability.
- Research Organization:
- Department of Physics and Astronomy, University of Maryland, College Park, Maryland 20742
- OSTI ID:
- 7183254
- Journal Information:
- Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 23:10; ISSN PFLDA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Kinetic approach to a pressure-gradient-driven tokamak resistive instability in the banana regime
Collisional effects on trapped particle modes in tandem mirrors
Related Subjects
700107* -- Fusion Energy-- Plasma Research-- Instabilities
700108 -- Fusion Energy-- Plasma Research-- Wave Phenomena
BOLTZMANN-VLASOV EQUATION
COLLISIONAL PLASMA
CURRENTS
DAMPING
DIAMAGNETISM
DIFFERENTIAL EQUATIONS
DISPERSION RELATIONS
DISSIPATION FACTOR
DISTRIBUTION FUNCTIONS
DRIFT INSTABILITY
ELECTRIC CURRENTS
ELECTRIC POTENTIAL
ELECTRONS
ELEMENTARY PARTICLES
EQUATIONS
FERMIONS
FUNCTIONS
INSTABILITY
LANDAU DAMPING
LEPTONS
MAGNETIC FIELDS
MAGNETISM
NORMAL-MODE ANALYSIS
NUMERICAL SOLUTION
PLASMA
PLASMA DIAMAGNETISM
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
PLASMA WAVES
SHEAR
TEMPERATURE GRADIENTS