Investigation of an X-band magnetically insulated transmission line oscillator

An X-band magnetically insulated transmission line oscillator (MILO)is designed and investigated numerically and experimentally for thefirst time. The X-band MILO is optimized in detail with KARAT code.In simulation, the X-band MILO, driven by a 720kV, 53kA electronbeam, comes to a nonlinear steady state in 4.0ns. High-powermicrowaves (HPM) of TEM mode is generated with an average power of4.1GW, a frequency of 9.3GHz, and power conversion efficiency of10.8% in durations of 0--40ns. The device is fabricatedaccording to the simulation results. In experiments, when thevoltage is 400kV and the current is 50kA, the radiated microwavepower reaches about 110MW and the dominating frequency is9.7GHz. Because the surfaces of the cathode end and the beam dumpare destroyed, the diode voltage cannot increase continuously.However, when the diode voltage is 400kV, the average power outputis obtained to be 700MW in simulation. The impedance of the deviceis clearly smaller than the simulation prediction. Moreover, theduration of the microwave pulse is obviously shorter than that ofthe current pulse. The experimental results are greatly differentfrom the simulation predictions. The preliminary analyses show thatthe generations of the anode plasma, the cathode flare and the anodeflare are the essential cause for the remarkable deviation of theexperimental results from the simulation predictions.