The Formal Nonequilibrium Theory of Partially Ionized and/or Nonuniform Gas Mixtures

Abstract

Starting from Boltzmann�like equations, moment equations for a general gas mixture are developed. The equations are closed, and the collision integrals evaluated, by using Grad's 13�moment approximations for the velocity distribution functions. The collision integrals are determined for all possible types of binary encounters, which include recombination and attachment, spontaneous fission and natural decay, charge exchange and elastic collisions, and excitation and fission� and fusion�like processes. The derivation of transport relationships is considered, while the extension of the results to include such direct radiative phenomena as absorption, photoionization, stimulated emission, and Compton scattering is also briefly discussed.