Study of the relationship between magnetic field gradient and operating range of flow rate for Hall thrusters

The development of all-electric, low-orbit satellite constellations requires low-power Hall thrusters with a wide thrust output. However, the efficiency at low flow rates decreases rapidly due to the deterioration of ionization. Although magnetic fields are widely used to optimize Hall thrusters, they are rarely used in wide-range variable flow conditions. In this study, we investigate the influence of the magnetic field gradient on the flow-rate range experimentally. It is found that a small-gradient magnetic field is helpful to improve performance at low flow rates. Then, the experimental results are explained by theoretical deduction, and the quantitative relationship between the flow rate and gradient is given. These conclusions provide guidance and a theoretical basis for designing high-performance, wide-range Hall thrusters.