Nonlinear Gyroviscous Force in a Collisionless Plasma

Belova, E.V.

Princeton University. Plasma Physics Laboratory.

关键词: Modifications;    Electrostatics;    Boltzmann-Vlasov Equation;    70 Plasma Physics And Fusion Technology;    Distribution Functions;   

DOI  :  10.2172/784555
RP-ID  :  PPPL-3569
RP-ID  :  AC02-76CH03073
RP-ID  :  784555

美国|英语

来源: UNT Digital Library

【 摘 要 】

Nonlinear gyroviscous forces in a collisionless plasma with temperature variations are calculated from the gyrofluid moments of the gyrokinetic Vlasov equation. The low-frequency gyrokinetic ordering and electrostatic perturbations are assumed, and an additional finite Larmor radius (FLR) expansion is performed. This approach leads naturally to an expression for the gyroviscous force in terms of the gyrocenter distribution function, thus including all resonant effects, and represents a systematic FLR expansion in a general form (no assumption of any closure is made). The expression for the gyroviscous force is also calculated in terms of the particle-fluid moments by making the transformation from the gyrocenter to particle coordinates. The calculated expression represents a modification of the Braginskii gyroviscosity for a collisionless plasma with nonuniform temperature. It is compared with previous calculations based on the traditional fluid approach. As a byproduct of the gyroviscosity calculations, we derive a set of nonlinear reduced gyrofluid (and a corresponding set of particle-fluid) moment equations with FLR corrections, which exhibit a generalized form of the ''gyroviscous cancellation.''