Development of a Low Current Heaterless Hollow Cathode for Hall Thrusters

Development of low current heaterless hollow cathode at Rafael is presented. The development process encircles cathode design, fabrication and experimentation activities aiming at nominal discharge current operation in the 0.1 A to 1 A range. Initially, manufacturing processes were developed to allow for the use of a variety of materials and geometries for optimal cathode thermal design. Subsequently, commercially available thermal simulation software was utilized to evaluate the temperatures formed on the electron emitter and cathode body. These temperatures were verified by experimentation, therefore validating the thermal model and corresponding assumptions. Cathode end-of-life was reached, as predicted by the thermal model, during operation at discharge current levels above 0.8 A due to excessive emitter heating. The end-oflife failure mechanism was analyzed and verified by comparing the observed phenomenon to literature. The described development campaign provides Rafael with heaterless hollow cathode development capabilities.