The effect of radiation on the spatial distribution of the temperature of subsonic flows of induction plasma

Results are given of measurements of the temperature characteristics of subsonic flows of air and oxygen plasma, generated by a VGU-4 $100$-kW induction plasmatron developed at IPM RAN (Institute of Problems of Mechanics of the Russian Academy of Sciences). The values of absolute intensity of spectral lines of oxygen and nitrogen atoms are used to measure the average (over the plasma jet diameter) temperature of atomic level populations (hereinafter referred to as atomic temperature) as a function of the parameters of the mode of generation, namely, the gas pressure in the range from $25$ to $200$ GPa and the power of anode supply within $29$–$72$ kW. The distributions of the atomic temperature of plasma ($T_a$) along the jet are obtained for some modes of generation. The radial distributions of the atomic temperature are obtained for some modes of generation of air and oxygen plasma. Their comparison with the temperature profiles obtained by the calculation of flows of equilibrium plasma in a discharge channel reveals a divergence for values of temperature on the flow axis exceeding $8000$ K.