Coupling of radiation, excited states and electron energy distribution function in non equilibrium hydrogen plasmas

Abstract

Some of the recent efforts in the state-to-state modeling of H/H2-based plasma are considered, with particular concern to the aspects of self-consistent coupling between the chemical kinetics, electron kinetics and radiation. These aspects are first illustrated in the case of a 0-dimensional model considering both optically thin and optically thick cases in recombining and ionizing regimes. In the second part of the paper, a 1-dimensional extension of the model is applied to study a steady normal shock generated in an H2/He plasma of interest in atmospheric entry problems. A radiation transfer equation is coupled to the model as well, to analyze the effect of radiation transfer on chemical kinetics and compare to the commonly used thin and thick plasma approximations. The most significant result is the influence of reabsorption on the concentration of excited states, which in turn creates additional structure on the electron energy distribution function through second kind collisions.