Influence of hollow anode position on the performance of a hall-effect thruster with double-peak magnetic field

A low-power Hall-effect thruster was designed with two permanent magnet rings. This Hall-effect thruster contains a symmetrical double-peak magnetic field with a gradient larger than that of conventional Hall-effect thrusters. The matching of the anode position with the magnetic field determines the performance of the thruster to a very large extent. This study investigates the laws and mechanisms that govern the front end of a U-shaped hollow anode at the inner magnetic separatrix, the outer magnetic separatrix, and the area between them and influence the discharge characteristics of the thruster. The study shows that with the increase of anode length, the ionization and acceleration zones are pushed down toward the channel outlet and even into the plume region. At the same operating point, both the thrust and the efficiency are the largest when the anode is placed between the inner and outer magnetic separatrices. When the anode is placed at the inner magnetic separatrix, both the thrust and the efficiency are small because of the heavy energy loss on the walls, despite the high degree of ionization. Finally, when the anode is at the outer magnetic separatrix, the performance of the Hall-effect thruster is the poorest because of the lower degree of ionization and larger divergence angle of the plume upon the shift of the ionization zone toward the plume region.