Pressure-gradient-driven tokamak ''resistive magnetohydrodynamic'' instability in the banana-plateau collisionality regime

Journal Article · Sat Jun 01 04:00:00 EDT 1985 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.864928· OSTI ID:5816123

Callen, J D; Shaing, K C

The moment equation approach to neoclassical processes is used to derive the linearized electrostatic perturbed flows, currents, and resistive MHD-like equations for a tokamak plasma. The new features of the resultant ''neoclassical magnetohydrodynamics,'' which requires a multiple length scale analysis for the parallel eigenfunction, but is valid in the experimentally relevant banana-plateau regime of collisionality, are: (1) a global Ohm's law that includes a fluctuating bootstrap current resulting from the ''parallel'' electron viscous damping (at rate ..mu../sub e/) of the poloidal flow due to the perturbed radial pressure gradient; (2) reduction of the curvature effects to their flux surface average because Pfirsch--Schlueter currents cancel out the lowest-order geodesic curvature effects: (3) an increased polarization drift contribution with B/sup -2/, replaced by B/sup -2//sub Theta/ where B/sub Theta/ is the poloidal magnetic field component. An electrostatic eigenmode equation is determined from delxJ = 0. For the unstable fluid-like eigenmodes, the new viscous damping effects dominate (by epsilon/sup -3//sup ///sup 2/) over the curvature effects, but the growth rates still scale roughly like resistive-g or resistive-ballooning modes, ..gamma../sub ..mu../tau/sub A/approx.n/sup 2/3/S/sup 1/3//sub N/..beta../sup 2/3//sub T/ x ( ..mu../sub e//..nu../sub e/)/sup 1/3/. Diamagnetic drift frequency corrections to these new modes are also discussed.

• Research Organization: Nuclear Engineering Department and Physics Department, University of Wisconsin, Madison, Wisconsin 53706
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5816123
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 28:6; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
BANANA REGIME
BOOTSTRAP MODEL
CLOSED PLASMA DEVICES
COLLISIONAL PLASMA
COMPOSITE MODELS
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
INSTABILITY GROWTH RATES
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
PARTICLE MODELS
PLASMA
PLASMA INSTABILITY
PLATEAU REGIME
PRESSURE GRADIENTS
SCALING LAWS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRAPPING