Instability of a current-carrying finite-beta collisional plasma


E.Y. Choueiri (EPPDyL, Princeton University)

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Published in Physical Review, E, 64(6):Article No. 066413, 2001.


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The micro-instability of a cross-field current carrying plasma in which the electrons collisions are important on the time scale of the oscillations and can be modeled with a BGK operator is studied using linearized kinetic theory under conditions of finite electron beta. The finiteness of beta allows for coupling between electrostatic and electromagnetic modes and necessitates dealing with the entire dispersion tensor. New fundamental features of the resulting instability are identified and contrasted with those found in previous studies of the lower hybrid current-driven instability in which either collisions or finite-beta effects were neglected. In the electrostatic limit collisions are found to revert from a stabilizing to a destabilizing role as the propagation angle with respect to the magnetic field is increased. As beta increases collisions play a more important role in destabilization, alter the character and extent of electromagnetic coupling, shift the instability to more perpendicular modes, and lead to a recapturing of some of the fluid-like properties the modes have in the electrostatic limit in contrast with their highly kinetic character in the collisionless limit.

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