2-D particle-in-cell simulations of high efficiency klystrons

Currently, klystrons employing monotonic bunching offer efficiencies on the order of 70%. Through the use of the core oscillation electron bunching mechanism, numerical simulations have predicted klystrons with efficiencies up to 90%. In this paper, we present PIC simulations of such geometries operating at a frequency of 800 MHz, with efficiencies up to 83% predicted thus far.