What is a Hall Effect Thruster?

Hall-effect thruster or Hall-current thruster is a type of Ion Thruster in which the propellant is accelerated by an electric field. Hall effect thruster consists of an acceleration chamber, an external cathode (negative electrode), an anode (positive electrode), and coils to produce a magnetic field. As the cathode is heated it starts emitting electrons and some of these electrons are attracted or pulled towards the anode. As a result, an electric field is produced which is directed along the axis of the acceleration chamber.

The coils inside the chamber generate a radial magnetic field which causes it to interact with the axial magnetic field and hence as a result, this high-strength magnetic field traps some of the electrons coming from the cathode, causing them to form into a circling ring at the downstream end of the thruster chamber. This circling ring of electrons creates hall current.

The propellant, which consists of an inert gas such as xenon or krypton at low pressure, is injected into the thruster's chamber through the positive anode injector and the circling ring of electrons collides with the inert gas’ atom turning it into a positive ion. This plasma of positive ions and the electron is accelerated outside the chamber by the electromagnetic force which results from the interaction of the radial magnetic field and the hall current. This process continues and the inert gas plasma is emitted outside at a high rate of speed.