Shielded electrostatic probe for nonperturbing plasma measurements in Hall thrusters

The use of shielded electrostatic probe to measure spatial plasma parameters of the quasineutral plasma in Hall thrusters was studied. The probe-induced perturbations could produce changes in the plasma parameters and discharge current on the order of their steady-state values, in Hall thrusters. The perturbations were explored by varying the material, residence time and penetration distance of various probe designs. In a set of experiments with a segmented shield probe, the thruster was operated in the discharge voltages of 200-500 V and input power range of 500 W-2.5 kW, while the probe-induced perturbations of the discharge current were below 4% of its steady-state value.