Electroncyclotron maser instability in relativistic plasmas
Abstract
The electroncyclotron maser instability is studied for the case of an anisotropic electron velocity distribution in the regime where the relativistic corrections to the wave dispersion are significant. Solution of the linear dispersion relation reveals that when the plasma frequencygyrofrequency ratio ω_{pe}/Ω_{e}<v_{te}/c, the instability is localized just below k_{⊥}c/Ω_{e}=1. The growth rate is then strongly peaked for emission at 90° to the magnetic field and is considerably larger than would be the case if the coldplasma dispersion theory were valid. These features are confirmed by electromagnetic particle simulations. The simulations also show that saturation results from perpendicular diffusion in velocity space and that the saturation level increases as ω_{pe}/Ω_{e} is decreased. A quasilinear analysis predicts that the saturation level scales as (Ω_{e}/ω_{pe})^{2} ω^{max}_{I}, where ω^{max}_{I} is the maximum linear growth rate. Applications of the maser instability to the generation of the Earth's auroral kilometric radiation are discussed.
 Publication:

Physics of Fluids
 Pub Date:
 September 1986
 DOI:
 10.1063/1.865492
 Bibcode:
 1986PhFl...29.2919P
 Keywords:

 Electron Cyclotron Heating;
 Magnetohydrodynamic Stability;
 Masers;
 Relativistic Plasmas;
 Computerized Simulation;
 Distribution Functions;
 Electron Distribution;
 Power Spectra;
 Wave Dispersion;
 Plasma Physics