Consistent analysis of a weakly ionized plasma and its boundary layer

The boundary layer problem of a weakly ionized collision-dominated plasma in front of a negative absorbing wall is considered. The electrons are assumed to be Boltzmann distributed. The ions are governed by symmetric charge exchange. The Debye length is small compared with the mean free path. A former kinetic analysis of the Knudsen layer is matched with an adapted macroscopic theory of the plasma body accounting for ionization, non-planar geometry and field-dependent ion mobility. The consistent analysis of plasma and boundary layer is illustrated with the examples of a cylindrical plasma column, a spherical probe in an infinitely extended plasma without ion generation, and a semi-infinite plasma with Saha ionization equilibrium distorted by wall losses. (author)