Rotational and Vibrational Temperatures of Atmospheric Double Arc Argon–Nitrogen Plasma

The spectroscopic technique is employed to study the emission of atmospheric argon–nitrogen plasma jet generated by an original dc double anode plasma torch. The molecular bands of the N2+ first negative system are observed at the torch exit and chosen to evaluate the rotational and vibrational temperatures in comparison with the simulated spectra. The excitation temperature (Texc≈9600 K) is determined from the Boltzmann plot method. The results show that the rotational, vibrational, electron and kinetic temperatures are in good agreement with one another, which indicates that the core region of atmospheric double arc argon–nitrogen plasma jet at the torch exit is close to the local thermodynamic equilibrium state under our experimental conditions.