A Fabry-Perot spectroscopy study on ion flow features in a Hall effect thruster

The exit velocity of singly-charged xenon ions is determined by means of Fabry-Perot interferometry at the exhaust of a high-power PPSX000 Hall effect thruster by analysing the Doppler shifted spectral profile of the 541.91 nm Xe+ ion line. A technique combining numerical simulations and CCD imaging is used to re-adjust the obtained velocity profiles in space, as this information is lost due to the accumulation of light along the line of sight. The applied voltage is varied from 200 to 900 V, and the xenon mass flow rate is varied from 5 mg s-1 to 15 mg s-1 to investigate the evolution of both the ion speed and the distribution of the accelerating potential over a broad power range. The goal of these measurements is twofold, namely, collecting reliable and extensive data and looking for a simple correlation between thruster parameters and corresponding accelerating potential distributions. Furthermore, this study reveals the presence of low velocity ions in the vicinity of the thruster channel exhaust