Numerical means for phase-resolved laser-induced fluorescence spectroscopy for dynamic studies in plasmas

Electric propulsion systems require extensive ground tests to properly characterize and validate thruster performance. Among the various plasma quantities measured, the ion velocity distribution function is particularly critical because it directly affects thrust and efficiency. Non-intrusive diagnostics, such as laser-induced fluorescence, are commonly used to measure ion velocities through Doppler shift analysis. In this study, we apply a numerical post-processing to conduct phase-resolved laser-induced fluorescence spectroscopy. This approach enables the spatiotemporal detection of ion velocities and the kinetic properties of neutrals in a Hall thruster that operates under strong breathing oscillations. The proposed technique can also be utilized in studies involving multi-parameter system characterization, where a quasi-periodic oscillation of one quantity prompts correlated changes in other properties.