Thermalization of a Fast Ion in a Plasma

Abstract

The question of the precise rate of thermalization of a fast ion in a plasma is of some interest in connection with several existing or proposed controlled thermonuclear devices. In this paper we follow a fast ion which is injected into a plasma in equilibrium. Specifically, we determine the time history of the probability distribution of this ion in velocity space. This is done by numerical integration of the linearized, space‐independent Fokker‐Planck equation with both the ion‐ion and ion‐electron interaction terms retained. The mean time of thermalization is calculated for several widely separated injection velocities. Some other properties of this single‐ion probability distribution are analyzed.