Effects of a nonuniform equilibrium electric field on ion temperature gradient instabilities
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (USA)
- Department of Applied Physics and Nuclear Engineering, Columbia University, New York, NY 10027 (USA)
A nonuniform equilibrium electric field oriented in the direction perpendicular to the magnetic field, and parallel to the density and temperature gradients, is considered. The effects of electric field gradients on the behavior of ion temperature gradient instabilities are examined. Electrostatic modes are considered in the local approximation for a shearless slab geometry, with phase velocities much lower than the characteristic electron thermal speed. The adiabatic response of electrons to the perturbing potential precludes the existence of Kelvin--Helmholtz (driven by velocity shear) and Rayleigh--Taylor (driven, e.g., by a centrifugal acceleration) instabilities. The velocity shear, caused by the nonuniform equilibrium electric field, has two principal effects. The first, proportional to the gradient of the velocity shear, causes both the well-known finite Larmor radius (FLR) modification to the {bold E}{times}{bold B} drift, as well as distortions of the particle unperturbed orbits. The second, proportional to both first and second spatial derivatives of the {bold E}{times}{bold B} drift velocity, shifts the cyclotron frequency, thereby modifying the effective FLR parameter, {ital k}{sub {perpendicular}} {rho}{sub {ital i}}. Generally, electric field profiles with a positive second derivative in {ital x} (the radial coordinate in a slab geometry) have a stabilizing influence.
- DOE Contract Number:
- AC02-78ET51013; FG02-87ER53257
- OSTI ID:
- 6145976
- Journal Information:
- Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Vol. 2:12; ISSN PFBPE; ISSN 0899-8221
- Country of Publication:
- United States
- Language:
- English
Similar Records
Single-fluid stability of stationary plasma equilibria with velocity shear and magnetic shear
Related Subjects
700107* -- Fusion Energy-- Plasma Research-- Instabilities
700108 -- Fusion Energy-- Plasma Research-- Wave Phenomena
ADIABATIC APPROXIMATION
CYCLOTRON FREQUENCY
ELECTRIC FIELDS
EQUILIBRIUM
HELMHOLTZ INSTABILITY
INSTABILITY
ION TEMPERATURE
LARMOR RADIUS
MAGNETIC FIELDS
ORIENTATION
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA WAVES
RAYLEIGH-TAYLOR INSTABILITY
SHEAR
SLABS
TEMPERATURE GRADIENTS
VELOCITY