The Vibrational Temperature in High-Enthalpy Jets of Atmospheric-Pressure Nitrogen Plasma

The paper deals with the spectroscopic determination of the temperature $T_v$ of population of low-lying vibrational levels of radiating electron terms of an $\text{N}_2$ molecule and $\text{N}_2^+$ molecular ion in different cross sections of a high-enthalpy jet of atmospheric-pressure nitrogen plasma. Use is made of the method of optimal fitting of the measured and simulated rovibronic spectra in some selected spectral range of the $(0$–$1)$ and $(1$–$2)$ bands of the first negative system of $\text{N}_2^+$ ion and of the method of finding $T_v$ by the integral intensities of molecular bands (sequence $\Delta_v = -1$ of the second positive system of $\text{N}_2$). The obtained values of vibrational temperature are compared to the previously found values of rotational temperature $T_r$ and electron temperature $T_e$. The pattern of variation of temperatures along the plasma jet in the zone of relaxation is discussed.