Effects of kappa distribution function on Landau damping in electrostatic Vlasov simulation

Abstract

Effects of non-thermal high-energy electrons on Langmuir wave-particle interaction are investigated by an initial value approach. A Vlasov-Poisson simulation is employed which is based on the splitting scheme by Cheng and Knorr [Cheng, C.Z. and G. Knorr, 1976: J. Comput. Phys. 22, 330-351.]. The kappa distribution function is taken as an example of non-thermal electrons. The modification is manifested as an increase in the Landau damping rate and a decrease in the real frequency for a long wavelength limit. A part of the analyses by the modified plasma dispersion function [Summers, D. and R.M.Thorne, 1991: Phys. Fluids, B 3, 1835-1847.] is reproduced for $\kappa = 2,3$ and 6. The dispersion relation from the initial value simulation and the plasma dispersion function compare favorably.