Electromagnetic Instability in an Electron Cyclotron Resonance Plasma

Abstract

An electron cyclotron resonance plasma was produced in a magnetic mirror field. Measurements of electron density, electron temperature, stored energy density, electron energy distribution, plasma light variations, and particle fluxes were made. An instability characterized by microwave emission below the electron cyclotron frequency, bursts of high-energy x-rays, particle losses along the magnetic axis, and variations in stored energy density was observed. The dispersion relation for transverse electromagnetic waves propagating in a plasma with an anisotropic Maxwellian electron velocity distribution with loss cones was solved numerically using parameters characteristic of this experiment and was found to yield instability frequencies and growth rates which agreed well with those observed.