Vibration-to-translation energy transfer in atmospheric-pressure streamer discharge in dry and humid air

Vibration-to-translation (VT) energy transfer in atmospheric-pressure streamer discharge is numerically simulated using a two-dimensional electro-hydrodynamic model. The model includes state-to-state vibrational kinetics in humid air and is coupled with the compressible flow equation of the gas fluid. The vibrational distribution of OO₂(v) reaches equilibrium more quickly than that of NO₂ (v), whereas the energy released from OO₂(v) does not increase the gas temperature. In humid air, the decay rate of the vibrational energy of NO₂ (v) is accelerated by the VT energy transfer through water molecules and the energy heats the gas. However, the increase in gas temperature due to VT energy transfer is not always seen because it competes with thermal diffusion.