[Study on the emission spectra of N2 plasma jet by AC glow discharge].

N2 plasma jet was generated from a nozzle using an AC discharge at about 15 kV. The emission spectra were obtained by using the concentration modulation spectroscopic technique. The dependence of spectral signal on the discharge current was discussed. It was found that the vibrational temperature decreased first and then increased downstream from the nozzle by measuring the emission spectra from different axial positions in the jet. A phenomenological model was presented to explain the vibrational temperature variation with different axial position z. The N2+/N2 ratio varied along the axis and the property of discharge in the experimental system was studied.