BACKGROUND

Ion accelerators with closed electron drift are also known as Hall-effect thrusters or Hall thrusters. Hall thrusters can be used on space vehicles for propulsion, station-keeping, orbit changes, or counteracting drag, for example. Hall thrusters generate thrust by supplying a propellant gas to an annular channel. The annular channel has a closed end with an anode and an open end through which the gas is discharged. A cathode introduces free electrons into the area of the open end. The electrons are induced to drift circumferentially in the annular channel by a generally radially extending magnetic field in combination with a longitudinal electric field, but the electrons eventually migrate to the anode. The electrons collide with the gas atoms to create ions. The longitudinal electric field accelerates the ions from the open end of the annular channel to generate a reaction force that produces thrust. In general, Hall thrusters come in wide range of discharge power configurations.

SUMMARY

A Hall thruster according to an example of the present disclosure includes an annular discharge region and an annular cathode concentric to the annular discharge region.

In a further embodiment of any of the foregoing embodiments, the annular cathode is circumscribed by the annular discharge region.

In a further embodiment of any of the foregoing embodiments, the annular cathode circumscribes the annular discharge region.

A further embodiment of any of the foregoing embodiments include an anode adjacent the annular discharge region.

A Hall thruster according to an example of the present disclosure includes inner and outer magnetic poles, and an annular discharge region between the inner and outer magnetic poles. The annular discharge region defines a central axis. A propellant gas feeder is operable to feed propellant gas to the annular discharge region. An annular cathode circumscribes the central axis, an anode, and at least one magnet magnetically coupled with the inner and outer magnetic poles to generate a magnetic field across the annular discharge region.

In a further embodiment of any of the foregoing embodiments, the annular cathode is circumscribed by the annular discharge region.

In a further embodiment of any of the foregoing embodiments, the annular cathode circumscribes the annular discharge region.

