Background

Hall thrusters are a widely-used class of spacecraft electric propulsion device. They are annular crossed-field devices in which a voltage drop is applied across a steady radial magnetic field. Electrons in the device become trapped in an strong azimuthal Hall current. They impact injected neutral atoms, ionizing them. These ions are then accelerated out of the channel by the electric field, which generates thrust.

Hall thrusters offer moderate to high specific impulse and high thrust density compared to other electric propulsion systems, and can achieve total efficiencies higher than 50%. They are commonly used for in-space propulsion for commercial communications and surveillance satellites as well as increasingly for deep space missions.