High-Power Microwave Generation by Virtual Cathode Oscillator

Summary form only given. High power microwave generation by virtual cathode oscillator has been studied both experimentally and by numerical simulation. The research objective is development of high-power microwave source that has relatively simple structure and matches well with typical pulsed-power generators. The lifetime and stability of the electron-beam diode is also tested in repetitive operation. The experiments were carried out by using repetitive pulsed-power generator "ETIGO-IV", with typical experimental parameters of diode voltage 400 kV, diode current 10 kA, and pulse width 150 ns. The results have shown maximum microwave power of ~120 MW giving beam-to-microwave efficiency of 3%. The microwave frequency is nearly 2 GHz with dominant microwave mode of TM₀₁. In the experiments, different cathode materials were tested and compared with each other in performance for hundreds of shots. Computer simulations were carried out by using three-dimensional, particle-in-cell simulation code "MAGIC". Numerical investigations involved studies of diode behavior, beam-field interaction, and configuration optimization. The simulation results were compared with the experimental results to give a combined evaluation for the performance of virtual cathode oscillator.