Extraction of Electron Current from the UM Large Area, ECR Plasma Neutralizer

Summary form only given. We report experiments, theory and simulations in which the Getty, large area ECR plasma source, has been applied as a neutralizer for space propulsion applications. This plasma source utilizes linear arrays of permanent magnets, placed in the end of a large, S-band microwave horn. Magnet bars are cross-polarized so microwaves propagate through with relatively low reflection. Large, ECR-resonant zones are created by the magnet arrays, where ionization occurs. Overdense electron densities up to 6 E11 /cc have been generated at the operating frequency of 2.45 GHz. Scaling measurements of electron current have been performed as a function of gas pressure, extraction voltage and microwave power. Theory and simulations are underway of ECR plasma ionization and heating in realistic magnetic fields