Transport phenomena in a partly ionized gas

Abstract

A closed system of transport equations for a multi component gaseous mixture was found in [1] in the “13 moment” approximation in Grad's method [2]. If the interaction between the particles (and this includes Coulomb particles) can be described in terms of collisions between pairs, an analogous system of equations can be written for ionized gas composed of an arbitrary number of uncharged (neutral) and charged components. Then, in contrast with [1], terms are introduced into the left-hand side of the equation to express the effects of the electrical and magnetic fields. A similar system of equations for a fully ionized two component plasma has been discussed recently in [3]. Normal equations of continuity, motion and energy serve as the lowest moments of the distribution function. Equations of motion for the separate gas components and the expressions for the tensors of viscous stresses and of thermal fluxes of particles, which are derived from the equation for second and third order moments, comprise a closed system which allow all the transport phenomena to be studied and the corresponding kinetic coefficients to be calculated. In this paper expressions have been obtained for viscosity and thermal particle flux tensors in a three component plasma (electrons, ions, neutrons and neutral particles). The derivation of the generalized Ohm's Law is dealt with for such a plasma taking into account thermal particle fluxes in the equations of diffusion. Expressions are obtained for the conductivity current along and transverse to the magnetic field including the conductivity due to pressure and temperature gradients.