Segmented electrodes in annual and cylindrical hall thrusters

In recent experiments, a 2 kW Hall thruster with segmented electrodes, which were made of an exceptionally low sputtering and low secondary electron emission carbon fiber velvet material, was operated in the discharge voltage range of 200 - 700 V. The comparison of the voltage-versus-current characteristics and plasma parameters of the Hall thruster with and without segmented electrodes indicates that the magnetic insulation of the segmented thruster improves with the discharge voltage at fixed magnetic field. The observations reported here also extend the regimes wherein the segmented Hall thruster can have a narrower plume than that of the conventional non-segmented thruster. The use of segmented electrodes is also studied for a miniaturized 100 W cylindrical Hall thruster. For an optimized variant of this thruster, we achieved performance improvements, including a 30-40% plume narrowing, reliable discharge initiation, and stable operation in the discharge voltage range of 50-600 V.