All Cavity-Magnetron Axial Extraction Technique

A compact axial π-mode extraction scheme, which is based on a patent by Greenwood, is demonstrated in conjunction with the UM/L-3 relativistic magnetron using the particle-in-cell code ICEPIC. Cases utilizing Greenwood's extraction technique were compared with power extraction using traditional radial waveguides. Average extracted power values in all simulated axial cases were found to be within +/-6.5% of the radial cases. Cases utilizing 85 ° and 90° sector waveguides were found to have efficiencies up to ten percentage points higher than the radial case. The best performing case was found to use a set of three axially oriented 90 ° sector waveguides, shorted on the upstream side, with the short located 15 cm from the center of the magnetron apertures.