Collisionless damping of electron waves in non-Maxwellian plasma

TL;DR

This paper challenges the traditional Landau damping theory by analyzing wave solutions in collisionless plasmas with non-Maxwellian electron distributions, revealing the presence of both damping and non-damping waves.

Contribution

It provides a critical analysis of Landau damping and demonstrates the existence of collisionless damping and non-damping waves in non-Maxwellian plasmas.

Findings

Both damping and non-damping electron waves exist in non-Maxwellian plasmas.

Landau damping theory does not account for all wave behaviors in such plasmas.

Wave solutions vary with different electron distribution functions.

Abstract

In this paper we have criticized the so-called Landau damping theory. We have analyzed solutions of the standard dispersion equations for longitudinal (electric) and transversal (electromagnetic and electron) waves in half-infinite slab of the uniform collisionless plasmas with non-Maxwellian and Maxwellian-like electron energy distribution functions. One considered the most typical cases of both the delta-function type distribution function (the plasma stream with monochromatic electrons) and distribution functions, different from Maxwellian ones as with a surplus as well as with a shortage in the Maxwellian distribution function tail. It is shown that there are present for the considered cases both collisionless damping and also non-damping electron waves even in the case of non-Maxwellian distribution function.