Thermally isolated thermionic hollow cathodes

Abstract

Embodiments relate to a hallow cathode with integral layers of radiation shielding. The hollow cathode includes an inner cathode tube that forms a gas feed to direct gas toward a downstream end, where the directed gas forms plasma. A heater element is positioned at the downstream end of the inner cathode tube, the heater element to heat the plasma. The hollow cathode further includes an outer cathode tube with a keeper electrode to sustain a bias voltage across a gap at a downstream end of the outer cathode tube for igniting the plasma. The integral layers of radiation shielding are connected by offset radial supports and are incorporated as a single element with either the inner or outer cathode tube, where the integral layers are nested with torturous conductive paths to reduce radiation and conduction losses from the downstream end of the inner cathode tube.

Dependencies are inferred from the claim text.