Effect of CO2 gas on the thermal-nonequilibrium ionization of nitrogen

Experimental measurements of electron density in a supersonic CO2:N2 gas mixture containing varying amounts of CO2 are reported. A series of current-voltage curves are recorded for mixtures with different CO2 contents at constant E/N = 3 x 10 to the -16th V sq cm. It is shown that adding CO2 in amounts typical for gas lasers (5-15 percent) decreases the electron density in the jet by no more than 50 percent. If N2 molecules excited to high vibrational states are involved in the ionization reaction, enough of them remain to support ionization even after energy exchange with CO2. It is concluded that the vibrational degrees of freedom of the laser-active molecules in homogeneous CO2 gasdynamic lasers can be pumped further by using a bulk discharge in a supersonic jet of nonequilibrium ionized gas.