Characterization of the effect of plasma screen electrical configuration on gridded ion engine operation

Ground testing of electric propulsion thrusters is critical to the prediction of both in-space performance and lifetime. However, there may exist significant differences between interpreted engine performance and lifetime as compared with space operation particularly at higher power, higher throughput operation. This work focuses on facility effects as related to gridded ion thrusters. Here we investigate the effect of the potential of the engine's plasma screen on overall engine performance. Depending on its potential and local plasma conditions, the plasma screen can give rise to uncertainty in the calculated thrust, beam neutralization, and overall engine performance. The effect of the plasma screen electrical configuration can be amplified due to the increase of CEX plasma at higher power levels. This work focuses on effect of the electrical configuration of the plasma screen potential on ion beam plume profile, near wall CEX plasma properties, plasma properties within the plasma screen, and on thruster performance at various thruster throttle conditions.