Gas temperature determination in a N2/Ar dielectric barrier discharge by diode-laser absorption spectroscopy and resolved plasma emission

The bulk gas temperature in a 30% N-2/70% Ar, short-pulsed (< 15 ns, FWHM) dielectric barrier discharge (DBD) was determined from the time-resolved diode-laser absorption of metastable Ar 4s' [1/2]degrees and the rotationally resolved N-2(+) 1st Negative and N-2 2nd Positive plasma emission. The gas temperature, derived from the N-2(+) and N-2, emission spectra, was determined from contour analysis of individual vibrational bands in the 1st Negative and 2nd Positive systems, while the temperature under the same discharge cell conditions was determined from the Doppler width of the metastable Ar absorption spectrum. The gas temperature determined for a low average power DBD at pressures of 10, 30, and 100 Torr and pulse repetition rates of 0.5-30 kHz was found to be slightly above room temperature (similar to350-400 K) and did not vary with pulse repetition rate.