Recirculating-Planar-Magnetron Simulations and Experiment

Microwave oscillation has been measured for the first time in a 12-cavity axial-magnetic-field recirculating planar magnetron, designed to operate in π mode at 1 GHz. The device operates with a -300-kV pulsed cathode voltage and a 0.2-T axial magnetic field, and oscillates at transverse currents exceeding 1 kA when driven by an electron beam pulselength between 0.5 and 1 μs. Microwave pulses were measured at frequencies between 0.97-1 GHz and achieved several hundred nanoseconds in length. Mode competition was observed between the π and 5 π/6 modes.