An Investigation Into Electron Temperature, Number Density, and Optical Emission Spectroscopy of the DC Hollow-Cathode Plasma Discharge in

In this paper, we measured the electron temperature and density of hollow-cathode plasma discharge as a function of discharge pressure and power in transition and collisional regions employing double-Langmuir-probe technique. Correction for the ion-current signal was made to compensate the reduction in the measured ion density due to high-pressure collisional processes within the sheath. The correction factor was found to increase from 9.94 to 48.23 as the pressure increased from 0.2 to 1.1 torr. Spectroscopic emission spectra were recorded, and the intensity of emission lines was investigated as a function of discharge power and pressure. The dominant dissociation fragments were found to be those of NO, , , and . An identification of the states leading to the observed emission lines and bands was made. Our results unambiguously show that the dissociation fragments and are mainly consumed in the production of NO. Effect of He gas on the discharge was found to be negligible.