MEASUREMENT OF HEAVY PARTICLE TEMPERATURE IN A RADIOFREQUENCY AIR DISCHARGE AT ATMOSPHERIC-PRESSURE FROM THE NUMERICAL-SIMULATION OF THE NO GAMMA SYSTEM

An optical diagnostic method particularly suitable for studying cold (2500-6000 K) air plasma properties when atomic line intensities are too weak to allow accurate measurements is presented. The method is based on a comparison between numerically simulated and experimental spectra of bands of the NO gamma system. It was applied to an air inductively coupled plasma at atmospheric pressure. This method allows the determination of the plasma temperature by measuring, on emission spectra, the widths of a rotationally non-resolved band at different heights; the uncertainty on such measured temperature values is about 250 K.