Hollow Cathodes Development at Sitael

Hollow cathodes are electron sources used for the gas ionization and the beam neutralization in Hall effect thrusters. Several hollow cathodes have been developed and tested at Sitael S.p.A. (former Alta S.p.A.), each intended for a specific power class of thrusters. An in-house numerical model has been used during the cathode design to define the relevant geometric parameters, in accordance with the thruster unit specifications in terms of discharge current, mass flow rate and lifetime. LaB6-based cathodes were successfully developed for Hall effect thrusters with discharge power ranging from 100 W to 5 kW. The design of a cathode for a 20 kW Hall thruster was also carried out. Experimental campaigns were performed in both stand-alone and coupled configurations. The comparison between experimental results and model predictions are here presented offering a sound theoretical framework to drive the design of future hollow cathodes.