High Current Plasma Cathode for Efficient Space Propulsion

A plasma discharge cathode for space propulsion capable of gt;100 A and employing a novel geometry that moves the bulk of the discharge outside of the hollow emitter insert. This allows the plasma volume to be larger than the cathode tunnel and thus able to deliver the very large currents (100 A or more) without increasing the emitter insert size. By keeping the plasma largely outside of the emitter insert, high performance very small emitters that operate at low temperatures can be used. This means much lower heating power and longer life and higher electron efficiency from these emitters.nbsp;We propose two state of the art cathode options:nbsp;A hollow scandate impregnated cathode capable of delivering 10A/cm2 at only 810ordm;Cb and 100 A/cm2 at only 970ordm;Cb.A hollow osmium-tungsten reservoir cathode capable of 10A/cm2 at 915ordm;Cb and 50 A/cm2 at less than 1000ordm;Cb.nbsp;We propose in Phase I to build two testers containing these cathodes and incorporating them into the geometry discussed above. We will test these, pulsed, to at least 100 A xenon discharge. e beam Inc. has more than 30 years of experience developing innovative cathode structures. The device is an important step forward for NASArsquo;s quest for a high power (100 kW) thruster to transport heavy payloads on long-range space flights.nbsp;