Relativistic and nonrelativistic magnetron experiments and a novel theory of relativistic crossed-field limiting current

Summary form only given, as follows. Relativistic magnetron experiments have generated over 200 MW total microwave output power. These experiments are driven by the MELBA long-pulse e-beam with parameters: Voltage = 0.4 MV, current = 1-10 kA, pulselength = 0.5 microsecond. The 6-vane magnetron is made by Titan and operates in the L-band near 1 GHz. Two types of cathodes were used: (1) a non-end-capped cathode with an Al explosive emission region in the center of the vanes, and (2) an endcapped cathode with a spherical knob placed at its end, beyond the vanes; the emission region is within the vanes. Endloss electron current is compared for the two cathodes. Microwaves are extracted from two opposing cavities and power measurements are summarized as a function of magnetic field.