Electrical Conductivity and Dielectric Permittivity in Microwave Non-maxwellian Plasmas

Abstract

The dielectric permittivity and electrical conductivity are important parameters that determine external characteristics of plasma media in terms of microwave propagation. In most cases, the calculation of these parameters is carried out in accordance with the widely used elementary theory, assuming a constant collision frequency of electrons with atoms and molecules. In this paper the results of computations of the real and imaginary parts of complex conductivity of argon plasma in the microwave band (f = 1–10 GHz) are presented. The plasma conductivity is computed from the two-term solution of the Boltzmann equation, and includes the velocity dependence of the electron collision frequency, as well as general case of the electron distribution function (EDF). Maxwellian, Dryuvestein, Bi-Maxwellian and Kappa EDFs were considered. The correction coefficients for a wide range of argon pressures (p = 10−3-10Torr) were calculated. According to the results obtained in this paper, it was demonstrated that the form of EDF could have a significant effect on the dielectric properties and conductivity of plasma. As an illustration, in some cases the corrected values of dielectric permittivity and conductivity exceed those calculated with classical theory, that is still preferable for technical calculations, up to several times and can not be discarded.