Investigation of correlation between thrust and anode temperature during transient operation of RAIJIN-66

The thrust performance of RAIJIN-66, a 2 kW-class Thruster with Anode Layer was investigated with respect to anode temperature change at a discharge voltage of 155 V, where propellant was not fully utilized. The upgraded dual pendulum thrust stand used for this study allows for thermal drift free thrust measurement. Correlation between the anode temperature and thrust was measured in real-time before the thruster and stand reached thermal equilibrium. An 8.7% decrease in thrust was reported when the anode temperature increased from 83 ºC to 130 °C. Using an analytical model to elucidate the effect of anode temperature on thruster performance, a good agreement between the predicted and measured thrust values was found for an ionization length of 1.1 mm, but the difference in slope suggests that the thrust performance is more sensitive to the gas temperature than expected. Thrust sensitivity is inferred for conditions in which the ionization mean free path is comparable or greater than the ionization length.