Ion boundary layer on a flat plate.

Abstract

A formal asymptotic theory is presented for the flow of a slightly ionized, continuum gas past a flat plate at large negative electric potential, in the limit of large ion Reynolds number. The appropriate equations are solved by a perturbation method. To lowest order there is an outer region where the flow is unperturbed, and an ion sheath region which is adjacent to the plate. Between these two regions there is a transition region. By solving the equations for the transition region in the next higher order, and by using the method of matched asymptotic expansions, appropriate boundary conditions are found for the ion sheath region. The downstream solution for all quantities of interest in the latter region is obtained by the method of characteristics.