Simulation of an injection-locked relativistic klystron oscillator

Summary form only given. The relativistic klystron geometry has been extensively studied to create modulated intense Relativistic Electron Beams (IREB) for production of high power microwaves (HPM) and driver beams for some accelerator schemes. Recently, a new variation of the Relativistic Klystron Oscillator (RKO) has been investigated by the Air Force Research Laboratory wherein an IREB is placed in a relativistic klystron geometry where the driver and booster cavities are close enough to couple to one another electromagnetically. Reflected particles are not needed to provide coupling to produce RF radiation. EM coupling provides feedback that allows the system to oscillate even after the external drive has been shut off. Thus, the device operates in an injection-locked mode. Simulations of this novel device are performed using MAGIC and ICEPIC. The simulations include the cathode, the interaction region, and the extractor. Results include frequency split due to cavity coupling, beam modulation, and power extracted from the beam. These results are in quantitative agreement with experiments, and demonstrate HPM oscillations from an RKO geometry without reflected particles.