Characterization of a C12A7 electride plasma-based cathode using different keeper orifice sizes

Abstract

For the operation of electric propulsion systems in space, efficient electron sources are crucial components. Hollow cathodes have been established for many applications since they allow sufficient current ranges at reasonable power requirements and have been proven to operate for several thousands of hours. New approaches are being evaluated to improve these cathodes’ general performance. This publication presents an extended characteristic of a heaterless plasma-based cathode using the emitter material C12A7 electride. The focus is on the relationship between the discharge potential and total discharge power over the discharge current. Furthermore, a characteristic of the discharge performance at lower mass flow rates is presented and discussed. The discharge potential is generally quite constant for a wide range of discharge currents, typical in the range of 30 V and only increases steeply for low discharge current ranges. Successful heaterless ignition and stable operation have been achieved down to 2 sccm krypton flow rate.