Time resolved optical emission spectroscopy in power modulated atmospheric pressure plasma jet

摘要

In this paper, the effects of the power modulation on atmospheric pressure plasma jet, operated in Ar+2%N2 mixture, are studied. Time resolved optical emission spectroscopy is used for the investigation. From line and band intensities, the excitation, vibration and rotation temperatures are calculated. Their evolution during the modulation period exhibits a strong dependence on modulation frequency. For higher modulation frequencies, there is significant discrepancy in rotational temperatures calculated from OH spectra and from N2+ spectra, which indicates that thermalisation time can reach milliseconds.