Anisotropic temperature effects on Landau damping in Kappa-Maxwellian astrophysical plasmas

Abstract

In many physical situations, especially in space, plasmas are found to have anisotropic power-law distributions, i.e., they can have one-dimensional Kappa distribution with high-energy tails in a preferred direction and a Maxwellian distribution perpendicular to it. In this work, we have used this distribution to study the Landau damping of electron-acoustic waves (EAWs) in the Kappa-Maxwellian plasma. A linear dispersion relation is derived, and the characteristics of the wave frequency and the Landau damping rate are studied by the influence of these energetic electrons. We show that the parameters such as the ratio of thermal speed in the Kappa distribution to that of the Maxwellian, the spectral index, and the ratio of cold to hot electron densities in the Kappa distribution significantly modify the propagation characteristics of EAWs.