Inclusion of radiation effects in plasma-neutral codes

Experiments on Alcator C-Mod have demonstrated edge plasma conditions with optically thick hydrogenic Lyman lines. In these high opacity plasma regions, the total neutral particle density and excited-state populations depend on the radiation field. Current edge plasma-neutral fluid codes ignore this dependence in their atomic physics models. For instance, collisional-radiative models are commonly used to define effective ionization, recombination and energy loss rates exclusively as functions of the local electron density and electron temperature. To include radiation effects in plasma-neutral codes, we are working towards two goals: extending the local atomic physics model to account for a spatially varying radiation field; and driving the extended model with results from a non-local thermodynamic equilibrium atomic kinetics and radiation transfer code. (orig.)