Investigation of 50 Hz Pulsed DC Nitrogen Plasma with Active Screen Cage by Trace Rare Gas Optical Emission Spectroscopy

Optical emission spectroscopy is used to investigate the nitrogen-hydrogen with trace rare gas (4% Ar) plasma generated by 50 Hz pulsed DC discharges. The filling pressure varies from 1 mbar to 5 mbar and the current density ranges from 1 mA·cm⁻² to 4 mA·cm⁻². The hydrogen concentration in the mixture plasma varies from 0% to 80%, with the objective of identifying the optimum pressure, current density and hydrogen concentration for active species ([N] and [N₂]) generation. It is observed that in an N₂-H₂ gas mixture, the concentration of N atom density decreases with filling pressure and increases with current density, with other parameters of the discharge kept unchanged. The maximum concentrations of active species were found for 40% H₂ in the mixture at 3 mbar pressure and current density of 4 mA·cm⁻². (low temperature plasma)