Kinetic model of gas heating of laser-produced plasmas by CO₂ laser in atmospheric air

A kinetic model was developed for theoretical investigations on laser-induced breakdown and gas heating in an N₂/O₂ gas mixture. This model calculates particle densities, electron energy, electron rate coefficient, vibrational temperature, gas temperature, and the other plasma parameters. The gas temperature was calculated from the potential differences in all chemical reactions. The analyses were performed for an N₂/O₂ mixture of 1 atm irradiated with a O₂ laser. The results show that the electron density of 10²³ m^-3 is the threshold of electrical breakdown and gas heating, and that the electron-ion recombination and the collisional de-excitation of vibrationally excited N₂(X¹Σ_g⁺) have a strong effect on the gas heating.