Real-time Plasma Diagnostic Tool for the investigation of Azimuthal Rotating Instabilities in Hall Effect Thrusters

The following paper reports about a non-intrusive diagnostic system able to measure the frequency of azimuthal instabilities inside the discharge channel of Hall Effect Thrusters (HETs) up to several hundreds of kHz in a real-time fashion.The innovative optical assembly, formed by an optimized sensor array, can help to drastically reduce the amount of processed data and the size of the opto-electronic front-end. The performances of the diagnostic system have been tested successfully during several tests on a HET in different regimes, showing an accuracy and reliability comparable with the state-of-the-art video recording methods. The high compactness of the developed sensor array opens new possibilities to perform simultaneously multi-channel or species-selective real-time measurements, while the reduced electronics and power consumption pave the way to miniaturized tools for on-flight diagnostics.