Transport of neutrals in the outermost region of a tokamak plasmas

Abstract

The transport of neutrals in the outermost region of a tokamak plasma has been studied using kinetic theory. Analytical expressions for the density profiles of hydrogen and impurity neutrals are obtained. It is shown that the inclusion of recombination increases the density of hydrogen neutrals in the blanket region by orders of magnitude. It is also found that the major contribution to the impurity neutral density, for impurities which have a resonant mutual charge exchange with hydrogen, comes from mutual charge exchange for moderately dense plasmas whereas for dense plasmas this comes from recombination.