Time-resolved electron temperature of a low power Hall thruster

Time-dependent behavior of electrons can be critically important to Hall thruster discharge behavior. Fast Optical Emission Spectroscopy (FastOES) is a non-invasive diagnostic capable of measuring the time-resolved electron temperature of the plasma. The FastOES approach splits the collected light and isolates two distinct wavelengths that are detected by photomultiplier tubes, and amplified to a measurable signal. These measured emission lines are paired with a collisional-radiative model to determine time-resolved electron temperature. Using this technique, the FastOES results show that the electron temperature exhibits both temporal and spatial variations within the Hall thruster. There is a dynamic relationship between the electron temperature and the discharge current, with the electron temperature consistently exhibiting an out-of-phase relationship in correlation with the discharge current. Additionally, a loose scaling relationship was identified, providing valuable insights into the complex interplay within Hall thruster plasmas.