Transport of neutrals in a multicomponent cool plasma mantle

Abstract

Transport of neutrals in a plasma, consisting of two species of ions and neutrals, across a plane plasma slab bounded between the wall and hot plasma is investigated using a kinetic approach. Analytical expressions for the neutral density profile and the velocity distribution functions have been obtained. For impurity elements like He, Ne, and Ar for temperatures T<10 eV, the neutral transport is controlled jointly by electron ionization and charge exchange and the penetration depth for neutral atoms of these elements is found to be somewhat larger than the penetration depth for neutral hydrogen atoms. In the temperature range 20 eV<T<100 eV the penetration of both the neutral species is governed mainly by electron ionization and the penetration depth for neutral hydrogen atoms is found to be nearly equal to that for neutrals of these elements. It is also noted that the impurity content in the plasma phase affects the transport of impurity neutrals weakly when 20 eV<T<100 eV and strongly for T<10 eV.