Expanded Semi-Empirical Model of RF-driven Nitrogen Gas Discharge

Nitrogen is the most abundant atmospheric gas with the strongest covalent bond. N₂ gas discharges are widely used in industry and scientific research. We report on the continued development of a power-mass balance model for an axisymmetric RF discharge [1-3] in nitrogen that includes the dominant physical processes such as axial and radial transport, molecular dissociation, ionization, excitation, wall loses, etc. The molecular gas brings additional complexity to the numerical model, which was originally developed for argon [4]. The model considers several molecular and atomic metastable levels. It also includes emission from the strongest systems that have been detected in experiment: 1st and 2nd positive, 1st negative and Lyman–Birge–Hopfield. Spectral data from vacuum EUV spectrometer and high-resolution NUV-NIR spectroscopic system [5] are presented and compared to the simulated data. Hysteresis of the light-to-plasma sources transition is predicted numerically and discussed.