Magnetic field effects on microwave gas discharge duplexer characteristics

An experimental investigation has been made to determine some of the effects of a confining magnetic field on a gaseous plasma within a duplexing device. Both parallel and crossed E and H field configurations were examined using a helium and a helium-neon Penning discharge. Temperature measurements indicate that magnetic confinement can lower the rf window temperature of gaseous discharge duplexing device by more than 50% at pressures below 0.5 torr. Leakage power can also be reduced by 50% or more in this pressure range, but the leakage level in the parallel field device is inherently too high for practical application. Reductions of up to 4.5 to 1 were obtained in the recovery time of helium in the 2- to 50-torr pressure range using a crossed-field configuration. By magnetically confining the plasma discharge of a gas duplexer, the performance can be significantly improved by lowering temperatures and gas clean-up rates.