Self-consistent modeling of DC and microwave nitrogen discharges and their afterglows

This report presents an investigation on the modeling of stationary DC and microwave nitrogen discharges and their afterglows, operating at pressures around one Torr and ionization degrees between 10(-7)-10(-4). The model is based on the self-consistent solutions to the electron Boltzmann equation coupled to the rate balance equations for the most important neutral and charged species, the wave electrodynamics characteristics and the gas thermal balance equation. The results are obtained as a function of the usual discharge operating parameters, namely gas pressure, discharge current or electron density, and tube radius. It is shown that the vibrationally excited molecules play a central role in the whole problem, ensuring a strong link between different kinetics and directly contributing to the mechanisms of dissociation and gas heating. Furthermore, vibrationally excited molecules in high vibration levels are in the origin of the peaks observed in the flowing afterglow for the concentrations of several species, such as N-2(A (3)Sigma(g)(+)), N-2(B (3)Pi(g)), N-2(+)(B (2)Sigma(u)(+)) and electrons, which occur downstream from the discharge after a dark zone as a consequence of the V-V up-pumping mechanism.