gyrokinetic theory, non-neutral plasma, gyrokinetic expansion, FLR


Gyrokinetic equations are derived for applications to non-neutral plasmas in constant, straight magnetic fields wherein E X B drift velocities are of the same order as thermal velocities. The ratio of the E X B rotation frequency to the cyclotron frequency and the ratio of the gyroradius to a plasma scale length are assumed to be of order epsilon and terms are retained in the gyrokinetic expansion to second order to include finite-Larmor-radius (FLR) effects. A mode equation is obtained for a non-neutral plasma in the infinite-length approximation. The singularities of this equation are compared and contrasted with the familiar mode equation from the cold-fluid approximation. A numerical investigation of m=1 perturbations for a pure electron plasma with parameters chosen to closely approximate those in the report by Driscoll [Phys. Rev. Lett. 64, 645 (1990)] reveals no exponentially unstable modes with significant growth rates and strongly suggests that finite temperature is not the source of the exponential growth seen in the experiments.

Original Publication Citation

Rasband, Neil S."Model equations from gyrokinetic theory for a non-neutral plasma to include temperature effects and applications to a plasma of infinite length." Physics of Plasmas 3 (1996): 94-13.

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Peer-Reviewed Article

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Physical and Mathematical Sciences


Physics and Astronomy