Characterization of Nitrogen Glow Discharge Plasma via Optical Emission Spectrum Simulation

Optical emission spectroscopy in nitrogen glow discharge plasma is simulated,andthe collision excitations and characteristic emissions of the species（N;,N;,N;,N）are investigatedby a Monte Carlo model for nitrogen molecular gas discharge.The excitation rates of the mainexcited states are calculated and the corresponding relation and relative magnitude between thedistribution of excitation rate of a certain excited state and the distributions of the emissionrates of various lines originating from this excited level are also explored.The simulated resultsare compared with the experimental measurements in two typical discharge conditions.Theluminescence mechanism of the line N;:391.4 nm is explained based on the microscopic plasmaprocesses.The cathode glow in N;discharge is found to be mainly caused by N+ impact excitationand the intensity of cathode glow decreases with the voltage.The corresponding relation betweenthe emission rate or intensity of the 391.4 nm line and the production rate and the density of N+is also examined.