Electron cyclotron resonance microwave plasma neutralizer for ion thruster systems

Summary form only given. We report the application of the Getty, large area, ECR-plasma source, as an electron source for the neutralization of ion thruster beams. This plasma source consists of a large waveguide horn in which the microwave output end is covered with cross-polarized rows of permanent magnets separated by slots. The large-area plasma is formed in the electron-cyclotron-resonant magnetic fields outside the magnet-bar slots. Typical microwave parameters are: frequency of 2.45 GHz, and power levels of hundreds of W. Electron densities have been measured to be overdense, at values up to 6 E11/cc at this frequency. Scaling studies are underway to raise the frequency to 6 GHz for a potential 6-fold increase in the electron density.