Self-Consistent Modeling of Volume and Surface Processes in Air Plasma

A self-consistent model for bulk and surface kinetic processes in low-pressure flowing discharges in N 2 -O 2 mixtures is presented. The model has a small number of input parameters and includes a large number of physical-chemical reactions that enable one to determine the concentrations of the different neutral (including NO and NO 2 ) and ionic species, as well as the populations of excited N 2 , O 2 , N, and O electronic states and N 2 vibrational levels, the density N e of free electrons, their average kinetic energy and transport properties, the electric field, the average (across the tube) gas temperature, and the wall temperature. The kinetic model for surface processes, which is coupled to that for the bulk plasma, takes into account the processes of physical and chemical adsorption and desorption of N and O atoms, surface diffusion of these atoms, and surface chemical reactions leading to the formation of gas-phase N 2 , O 2 , NO, and NO 2 molecules. The probabilities for surface losses of N, O, and NO and the rates for surface production of gas-phase NO and NO 2 molecules have been obtained as a function of the surface temperature and the fluxes of gas-phase N and O atoms and NO molecules to the surface