Description: A > 100 A plasma discharge cathode for ionization and neutralization is offered. It will incorporate two breakthrough cathode options. These allow much higher loading, lower temperature, and smaller size than current art. In order to utilize these smaller cathodes, a novel geometry is offered. The bulk of the discharge is moved outside the hollow cathode to a region between the cathode and an orifice cup which surrounds the cathode. This allows expansion of the plasma volume to a magnitude at which it can easily supply the large currents (> 100 A) requested. Yet the plasma is still confined and maintained at a density that minimizes trans-impedance from the cathode through the plasma, through the orifice to the anode. This allows very large electron currents at very low anode voltages (under 20 volts). The two cathodes are hollow scandate and hollow reservoir with an osmium tungsten insert. Both were perfected in the last 10 years. Scandate cathodes provide > 100 A/cm2 at under 1000º Cb.

Benefits: Very powerful (100 kW) thrusters are needed to move heavy payloads to Mars, the moon and other planets. These plasma cathodes help meet this requirement.

For orbit raising of heavy geosynchronous satellites.