Source for Neutralizing an Electron Beam Propagated from a Sounding Rocket

A Hidden Anode Plasma Contactor (HAPC) instrument has been developed for the Beam-Spacecraft Plasma Interaction and Charging Experiment (B-SPICE), which will be launched on a sounding rocket in late 2024. B-SPICE uses an electron beam assembly (EBA) with the HAPC to evaluate spacecraft charging as a function of the operating regimes of the HAPC and EBA. The experiment will improve the understanding of active spacecraft charging mitigation when electron beams are used on satellites in the magnetosphere.

The HAPC is comprised of a heaterless hollow cathode assembly (HCA) and an enclosed or “hidden” anode (HA) element acting as the primary ionization stage to generate Kr ions at prescribed rates ranging from a few milliampere up to an ampere. The HA dramatically increases ion production rates beyond what the hollow cathode alone can achieve, but in a very compact shape factor compared to traditional plasma sources. This increased ion production rate allows for effective charge mitigation on a spacecraft that is emitting a high current electron beam. The Kr ions emitted by the HA have charge states ranging from 1 - 3 and have directed energies ranging from ~30-300 eV depending upon the operating condition.