Low-Current Hollow Cathodes for Hall Effect Thrusters

Two low-current hollow cathodes, HC1 and HC3, were respectively designed at Sitael for a nominal discharge current of 1 and 3 A, as their name suggests. A numerical model developed in-house was used to select the cathode geometry, as well as to estimate the cathode expected lifetime on the basis of the emitter evaporation. HC1 was tested with a barium-based dispenser emitter, as alternative with respect to lanthanum hexaboride (LaB6). The ignition procedure was assessed, performing repeated cycles to verify the robustness of the heater. A new design of HC3 with a bariumbased emitter was also carried out. Future developments will include an improved mechanical design of the cathodes and additional experimental campaigns, to assess the cathode performance and lifetime and to further validate the theoretical model.