FEASIBILITY DEMONSTRATION OF A NEW PLASMA DIAGNOSTIC PROBE

摘要

The purpose of this contract was to demonstrate the feasibility of utilizing the Thomson-scattered radiation of a ruby laser to determine electron temperature and density in a helium plasma. A thyratron tube was modified to create the plasma and a spectrometer was used to observe the Doppler profile of the Thomson-scattered radiation. Langmuir-type probes built into the modified thyratron were used as an independent check on electron density, and temperature. There was little correlation between the laser scattering and the check provided by the Langmuir probes. A precise determination of electron temperature was not realized using the laser scattering data. An electron density of approximately 1015 per cubic centimeter was, however, deduced from the magnitude of the scattered energy. Opposed to this was a value, approximately 6 z 10 12 per cubic centimeter, derived from the Langmuir probe data. Theoretical effort supports the laser scattering data and negates the validity of the Langmuir probe data. From this it is inferred that this diagnostic technique is. sound even though the results do not completely demonstrate feasibility.