Role of a Conducting Vacuum Chamber in the Hall Effect Thruster Electrical Circuit

The role of the electrically conductive vacuum chamber wall in the completion of the discharge circuit of a Hall effect thruster is experimentally investigated. The Aerojet Rocketdyne T-140 laboratory-model Hall effect thruster, operating at a discharge voltage of 300 V, a discharge current of 5.16 A, and an anode flow rate of 5.80  mg/s, serves as a representative Hall effect thruster testbed. The nominal facility operating pressure during thruster firings is 4.9×10−6 torr, corrected for xenon. Two 0.91×0.91  m, square aluminum plates are placed adjacent to, but electrically isolated from, the walls of the stainless-steel vacuum chamber at two locations with respect to the center of the thruster exit plane: 4.3 m axially downstream along the thruster centerline and 2.3 m radially outward centered on the exit plane. The plates are configured in three distinct electrical configurations with corresponding measurements: 1) electrically grounded plates with measurements of currents to ground, 2) electrically ...