Measurement of Neutral Xenon Using Two Photon Radar REMPI and Laser Induced Fluorescence

ABSTRACT: Two separate diagnostic techniques are proposed for measuring concentrations of neutral xenon in Hall thruster research: radar REMPI and a variant of laser-induced fluorescence. Both methods have the potential to provide nonintrusive measurements at millimeter-level spatial resolution and microsecond-level time resolution, and both have already been demonstrated at xenon molecule concentrations of around 10^18 per cubic meter in non-optimized setups. In the proposed study, optimization of both techniques will be explored to determine the feasibility of detecting lower concentrations, with a target of 10^13 per cubic meter, which is needed for obtaining a better understanding of Hall thruster processes. The two methods will be compared and contrasted, and a recommendation will be made on which is most likely to enable the desired diagnostic.; BENEFIT: A diagnostic capable of measuring neutral xenon concentrations in plasmas will help elucidate fundamental plasma physics in practical test facilities. This improved understanding should lead to improvements in several plasma based technologies, such as longer lasting more efficient satellite thrusters. Modeling of plasma dynamics in Hall thrusters is currently limited by the lack of available data needed for validation. The diagnostic would help provide data that enables better models, leading to cost savings in future satellite propulsion systems. Other plasma technologies that could see cost benefits include water decontamination and purification, plasma processing, and plasma micro/nano-fabrication.