Single-Particle Cyclotron Radiation near Walls and Sheaths

Abstract

A particle which moves perpendicular to a magnetic field while undergoing periodic elastic collisions with a rigid wall emits radiation which is rich in higher harmonics. Collisions with a sheath, instead of a wall, also produces radiation of this sort. The resulting radiation is calculated utilizing a simplified model of a sheath and also assuming an exponential plasma density distribution, and is then compared with experiment. One can fit either the observed spectral shape or the observed intensity, separately, but a simultaneous fit is rather difficult. The best results are obtained for a sheath thickness of the order of a Debye length.