KINETIC DESCRIPTION OF ELASTIC PROCESSES IN HYDROGEN-HELIUM PLASMAS

Recent experiments with high density divertor plasma operation in tokamaks and future tokamak design projects have revived interest in the much earlier work on elastic collision processes between neutral and charged components in hot plasmas, In revisiting these papers, we employ classical methods to calculate deflection functions, cross sections and collision rates for the most important of such elastic collision processes. A phyiscally motivated cut-off procedure for the model interaction potential function is introduced. An algorithm for implementation of such processes into kinetic Monte Carlo neutral gas transport models is described, which accurately accounts also for possible singularities in the deflection function. Data fits for the relevant quantities are provided for hydrogenic and helium species, The relevance of elastic neutral-ion collisions is illustrated by a numerical simulation of an ITER relevant divertor model.