Causes of arcing in cw CO2 convection laser discharges

The factors causing glow-to-arc transition in volume-dominated molecular gas discharges have been analyzed in terms of the collisional processes taking place in the plasma. It has been shown that arcing can be initiated by the growth of disturbances in either vibrational or translational temperature. Calculations indicate that thermal and/or vibrational instabilities will occur for most conditions of importance to high-power cw CO2 convection lasers, and that the growth time for these instabilities is typically on the order of 1 msec.