Kinetics versus thermodynamics on CO2 dissociation in high temperature microwave discharges

Recent experiments by Groen et al (2019 Plasma Sources Sci. Technol. 28 075016) on CO2 activation at high translational temperature (3500 T-g < 5500 K) are analyzed with a self-consistent code describing the vibrational kinetics of reacting CO2 together with CO and O-2 and the corresponding electron Boltzmann equation. The kinetics results are compared with the corresponding thermodynamics values. This comparison shows that the major components of the mixture, i.e. CO and O can be described by the thermodynamic approach, while the other minor components present large deviation from equilibrium. A qualitative agreement is found between experimental and theoretical values of electron density, E/N and electron temperature in both diffuse and contracted regimes. The theoretical vibrational distributions as well as the corresponding electron energy distribution functions present non-equilibrium effects even at the considered high translational temperature.