Spectroscopic investigation of corona discharges in liquid and high density gaseous nitrogen

This paper presents the results of a spectroscopic investigation of corona discharges in high pressure nitrogen gas (up to 10 MPa) and in liquid nitrogen. In the gas, rotational temperatures T_r and vibrational temperatures T_v of the excited state 2s⁺ (C³Π_u) have been deduced from a comparison between computer generated synthetic spectra and experimental ones. In the liquid phase, only the vibrational temperature could be measured. The ratio of (0-0) band intensity of the 1s^- transition on (2-5) band intensity of the 2s⁺ transition has been determined as a function of discharge current and density. From this ratio, the mean electron energy, ⟨ε⟩, has been estimated