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.

Plasma boundary phenomena in tokamaks

“…NIMBUS [221], a 3-D code developed for JET, has been employed in a stand-alone mode [23] and has also been incorporated in a plasma code. A number of other Monte Carlo models [281][282][283][284][285][286][287][288][289] and non-Monte Carlo models [290][291][292][293][294][295][296][297][298][299][300][301] have also been employed.…”

Theory and Modelling of Helium Enrichment in Plasma Experiments with Pump Limiters

“…Thus, as an illustration, it is sufficient to develop only an approximate solution to the slab problem, but one which adequately describes how the differential atomic physics processes are manifest in yielding helium enrichment. We note here that simple, analytic neutral atom transport models have also been used to investigate the feasibility of the cool plasma mantle concept [22].…”

Transport of neutrals in the outermost region of a tokamak plasmas

“…Tendler & Chhabra (1982) for the first time applied kinetic theory to the problem of neutral gas penetration across a two-element blanket. These authors (Tendler & Chhabra 1982) neglected the phenomenon of mutual charge exchange and recombination, hence their study is not applicable to important impurities like oxygen, nor to moderately dense plasmas. Tendler (1982) extended this work to oxygen impurity.…”