DISSOCIATION LEVELS IN FAST-AXIAL-FLOW CO2-LASERS - A QUANTITATIVE MODEL

A plasma chemistry model is presented that explains the observed CO2 d issociation levels in a closed-cycle fast-axial-flow CO2 laser. The mo del includes reactions between the neutral species CO2, CO, O, O-2, O- 3, H2O, and OH, and the negative ions O- O-2(-), CO3-, and CO4-. Disso ciation rates are computed by solving the electron Boltzmann equation for experimental values of the reduced field EIN. It is found that gas replenishment and the neutral recombination reaction between CO and t he OH radical are the most effective mechanisms to suppress the CO con centration in the gas circuit. The influence of CO2 dissociation on th e laser output power level is discussed. (C) 1995 American Institute o f Physics.