Hollow cathode conditioning and discharge initiation studies

Hollow cathodes are used for a wide variety of applications, including challenging ones like plasma contactors for sounding rocket experiments. Existing hollow cathode designs cannot be started in the short amount of time available during sounding rocket flight, however, a fast-starting hollow cathode is being designed in Colorado State University to address this issue. In the framework of fast-staring cathode development, a study of cathode conditioning and activation was performed where desorption and outgassing of contaminants from a cathode during conditioning was studied. Cathode ignition times are correlated to no-flow (vacuum) emission levels, and a model that describes the vacuum electron emission from a cathode (that is coupled to a 3D thermal model) is presented and validated against experimental data.