IONIZATION EQUILIBRIUM IN FLOWING CO2-LASER MIXTURES

The reduced electrical field strength is a key physical input to plasm a chemistry and vibrational kinetics models of CO2 laser discharges. I n this paper the different processes that influence the ionization equ ilibrium are studied and a tractable model is constructed from which t he self-sustaining electrical field in the positive column of a flowin g CO2 laser mixture is derived. Apart from the charged particle losses related to the turbulent flow, a number of plasma-chemical effects su ch as CO2 dissociation and water contamination are included in the ana lysis. The total negative-ion density is denoted as a critical quantit y in explaining experimental reduced electrical field values.