On the relaxation of non-thermal plasmas

The collisional relaxation of various plasma distributions that are initially far removed from thermal equilibrium is investigated numerically using a Fokker-Planck code. It is shown that self-similar and kappa distributions do not remain self-similar or kappa, and that this is due to the velocity dependence of the effective collision frequency. For the relaxation of an isotropic two temperature plasma it is shown that a constant-temperature three-component distribution function is a plausible model for analytical calculations. Investigation of the relaxation of bi-Maxwellian plasmas resolves some discrepancies that have arisen from earlier studies.