Temperature measurement of nonequilibrium high temperature plasma by means of N2+ first negative band

In the case of rare gas plasma, there are electron temperature and heavy particle temperature as the important temperature, and the former can be determined relatively easily by the measurement of emitted line spectrum intensity, but the measurement of high heavy particle temperature is difficult because thermocouples cannot be used, and the form of spectrum lines is controlled by Stark spread. In this study, the nonequilibrium argon plasma generated by a newly improved Maecker type plasma generator was taken as the object of measurement. The measurement of temperature was attempted by the comparison of the experimental intensity distribution of the first negative band system of N2+ molecular ions which are easy to be generated at high temperature, by mixing a minute quantity of nitrogen, with the artificial band spectrum intensity distribution theoretically calculated by taking the equipment width of a spectrometric system into account. In this study, the objective was limited to temperature measurement, the theory was approximated and simplified so as to be calculable with a small desktop computer, and only the relative intensity distribution was treated. The experimental setup, the principle of measurement and the results are reported. (Kako, I.)