VOLUME NO.9 – FIRST QUARTER 1966 Plasma Properties by Spectroscopic Measurements Transmission Design for Aircraft Gas Turbines

摘要

Spectrographs measurements of plasma properties in direct conversion devices and a cesiated helium arc have been made and a summary of these studies is presented herein. The line reversal technique was used to measure the electron temperature in a magnetoplasma-dynamic (MPD) generator and appeared to give good re¬sults;accuracies should be within +75°K. Both the ab¬solute intensity and relative line intensity methods were used to measure electron temperature in a thermionic generator. The absolute line intensity technique was ex¬cellent in that it provides a high sensitivity except at near peak line intensity conditions. There are, however, inherent in this method the uncertainties in the accuracy of the transition probabilities. Data scatter in the relative line intensity method made it difficult to use and the accuracy was seriously in doubt. The differential line ratio method developed at the Allison Division of General Motors eliminates the need for transition probabilities, spectral calibration of the photographic plate, and use of a radia¬tion standard. Although it has not been used extensively to date, it can be concluded that it is relatively easy to use and should improve the accuracy of electron temperature measurements.