Propellant Thermal Management Effect on Neutral Residence Time in Low-Voltage Hall Thrusters

The effects of anode temperature on the performance of a 4.5 kW Hall-effect thruster are investigated. The approach separates the location of gas injection from discharge current collection using an anode band, which removes the main mechanism that heats the gas distributor. A thermal model predicts a 270 K reduction of the gas distributor temperature, which corresponds to a 28% increase in the propellant residence time. Collection of the discharge current on the anode band, which is upstream of the bulk Hall current region, generates a 10% increase in ion current density at the thruster centerline for discharge voltages of 100, 125, and 150V at a xenonmass flow rate of 5 mg∕s. The initial reduction in neutral velocity with the anode band is counteracted by the influence of the channel wall temperature,which increases the neutral velocity of the particles by up to 25%greater than the velocity at the gas distributor exit plane. This reduces the potential thruster efficiency improvement from 5.5 to 2.5%. The selected downstream location of the anode band results in a 6–10% increase in discharge current compared with current collection on the gas distributor.