MODELING OF PLASMA-CHEMICAL REACTIONS IN GAS-MIXTURE OF CO2-LASERS .2. THEORETICAL-MODEL AND ITS VERIFICATION

In the paper we have modelled plasma-chemical reactions in the CO2 low pressure, DC excited lasers. A good agreement of theoretical and experimental results has been achieved. It has been proved that neglect of reactions with electronic excited species or heterogeneous recombination leads to almost 50% overestimation of CO2 equilibrium conversion. The relation of CO2 equilibrium conversion to the reduced field E/N, pressure and current density depends on discharge conditions and mainly on the role played in discharge by ambipolar diffusion. This role decreases with an increase of the discharge diameter and of the mixture convection velocity. The CO2 equilibrium conversion increases with growth of E/N and j and with decrease of pressure for discharges in small, sealed-off laser systems. The CO2 equilibrium conversion is not always a monotone function of p in large, convection cooled lasers. It does not depend so much on E/N as the electron temperature alone if conversions in different mixtures are compared.