Identification of Drift-Cyclotron Loss-Cone Instability in a Plasma and Suppression by Radio-Frequency Field

Abstract

An instability, which appears near the ion cyclotron frequency, is observed in the plasma reflected by one side mirror. The instability is identified as the drift-cyclotron loss-cone instability by comparing the experimentally determined dispersion relation with the theory. It is demonstrated that this instability can be suppressed by the high frequency electric field excited in a resonant cavity. The mechanism of suppression is attributed to the modification of the loss-cone distribution due to the ponderomotive force which pushes back the plasma.