Prototype Development of a Hollow Cathode for Hall Thruster Application

The rapid growth of the satellite industry has increased demand for efficient propulsion systems, with electric propulsion, particularly Hall thrusters, gaining attention for their high specific impulse. Hall thrusters need a reliable electron source for plasma generation and ion beam neutralization, typically provided by hollow cathodes. In general, hollow cathodes use external heaters to initiate thermionic emission, subsequently relying on ion bombardment for self-heating during steady-state operation. This study presents the design, fabrication, and preliminary testing of a hollow cathode intended for 1–5 A class discharge currents for low-power Hall thrusters. The hollow cathode has a length of 3 cm, with an orifice diameter of 0.5 mm and a keeper diameter of 2.3 mm. Lanthanum hexaboride (LaB₆) was chosen as the insert material for its thermal and discharge stability. Key design parameters were based on theoretical models and previous literature. A prototype was developed and tested in a vacuum chamber to evaluate ignition behavior, discharge stability, and current density. In the presentation, detailed studies of the prototype hollow cathode will be presented.