Air Collisional-Radiative Modeling with Heavy-Particle Impact Excitation Processes

This paper reviews the electron- and heavy-particle impact processes governing the population/depletion of the states of N, O, N2, and , which can be significantly affected by nonequilibrium conditions while strongly radiating in lunar-return shock layers. The collisional-radiative model developed in this work includes electron-impact excitation, ionization, heavy-particle impact excitation, vibration-electron, vibration-translation, dissociation and bound-bound radiative mechanisms. The available experimental and theoretical reaction rates governing these processes were critically reviewed to produce a reliable set of rate constants. The collisional-radiative model was then applied to typical nonequilibrium thermodynamic conditions encountered during lunar-return Earth reentry. The effect of heavy-particle impact processes is discussed.