ASYMPTOTIC ANALYSIS FOR A PARTICLE-TRANSPORT PROBLEM IN A MOVING MEDIUM

In this paper we discuss the derivation of the diffusion theory for a linear particle transport in a moving gas. We perform the asymptotic a nalysis for a one-dimensional linear BGK model problem with a shifting Maxwellian which describes the time evolution of the spatially depend ent electron distribution function in a moving weakly ionized host med ium. The modified (compressed) Chapman-Enskog expansion procedure is a pplied to find the asymptotic solution for small mean free path epsilo n, showing that the difference between the exact and asymptotic soluti ons is of order epsilon(2), uniformly in time for arbitrary initial da ta.