Conductivity and Permittivity in Plasma With Nonequilibrium Electron Distribution Function

Abstract

Electron conductivity and dielectric permittivity are essential parameters that determine the external characteristics of laboratory and space plasmas in terms of electromagnetic (EM) wave propagation. In most problems, $\sigma $ and $\varepsilon $ are calculated using the elementary theory under the assumption that the electron distribution function (EDF) is under equilibrium (Maxwellian). But, in real plasma, the EDF is, as a rule, non-Maxwellian. Therefore, the form of EDF can significantly affect the characteristics of various processes involving electrons. In this article, the calculations of the correction coefficients for conductivity and permittivity in argon were performed in a wide frequency range for typical two-temperature EDFs, with which almost any EDF in the laboratory and ionospheric plasma can be approximated. The results show that the form of EDF has a significant effect on the conductivity and the permittivity in plasma. Most substantial differences are observed under conditions when the frequency of the EM wave is less than the transport electron–gas collision frequency of electrons.