SPECTROSCOPIC INVESTIGATIONS OF HIGH-CURRENT HOLLOW-CATHODE DISCHARGES IN FLOWING NITROGEN AT LOW PRESSURES

The spontaneous emission from hollow-cathode discharges in flowing nitrogen is investigated spectroscopically. The vibrational energy distributions in the C3Πu state of N2 and the B 2Σu+ state of N2+ are studied as a function of discharge current, magnetic-field strength, and gas flow. The rotational energy distributions in these electronic states of N 2 have also been determined. The effective rotational and vibrational excitation temperatures are found to be low, TR≈2000°K and TV≈10 000°K respectively. The electronic excitation of N +, the dominant emitting atomic species, is found to correspond to much higher temperatures, Texc=35 000°K. © 1970 The American Institute of Physics.