MEASUREMENT OF EXCITATION AND ELECTRON TEMPERATURE IN A NITROGEN PLASMA

Abstract : The objective of the work was to measure the atomic line radiation of nitrogen in the spectral range from 7000 to 12,000 A and to examine the population distribution of excited states to determine if a Boltzmann distribution existed and consequently whether an excitation temperature could be defined. Simultaneous measurements using Langmuir probes were made to determine electron temperatures. These measurements were applied to a low-density plasma produced in an arc-jet and expanded into a low-pressure chamber. A one-meter Czerny-Turner scanning spectrometer was used to record the atomic line spectra. Results indicate a difference in the spectroscopic temperature measurements and Langmuir probe measurements of approximately 2000K. Reasons for this difference are discussed.