Measurement of heat flux in discharge channel of hall thrusters

A study was conducted to perform measurements of heat flux in discharge channel of hall thrusters. The study was carried out on an Aton-type Hall thruster in a 1.5 × 4 m vacuum chamber with two diffusion pumps, one rotary pump, and three mechanical booster pumps. The outer insulator of the thruster had an inner diameter of 71 mm and a gap of 15 mm wide. A slit measuring mm wide was provided in the outer dielectric wall to measure the ionic current and ions average velocity toward the wall. The ionic current was measured using a probe of coaxial structure with an internal tungsten wire 0.3 mm in diameter within Al₂O₃ tube shield. The average velocity of ions in the plume was measured with a multigrid probe. It was observed that the collimation angle of the probe was determined by the diameter and the distance between the first grid and the collector and it ranged between 20-30 degrees.