Experimental investigation of Hall thruster magnetic field topography
Magnetic field measurements are made in the discharge channel of the Plasmadynamics and Electric Propulsion Laboratory (PEPL) 5 kW P5 Hall thruster. The P5 operating conditions were maintained throughout the experiment at a discharge voltage and current of 300 V and 5.4 A respectively. At this 1.6 kW operating condition the magnetic coil currents were operated at 2 A for the outer coils and 3 A for the inner coil. Two miniature Hall probes are employed to measure the axial and radial magnetic fields simultaneously inside the discharge channel while the P5 thruster is operating with and without a plasma discharge. The magnetic field measurements are accomplished with minimum disturbance to the plasma and the operation of the thruster with the PEPL High-speed Axial Reciprocating Probe (HARP) system developed by James Haas. Data are presented at axial locations ranging from the anode to ten centimeters downstream of the exit plane and at radial positions covering the width of the discharge chamber. The magnetic field profiles are compared to determine the effect that the plasma discharge has on the static magnetic field topography. Magnetic field profiles for the case with plasma discharge are compared with previously measured plasma potential, temperature and number density data and conclusions are drawn regarding the nature of the ionization and acceleration regions with respect to the magnetic field topography in the P5 Hall thruster.
