Comparison of recent high efficiency vircator

Summary form only given. The vircator has suffered from low efficiency (2-3%) and unstable output since its conception in the 1960s. The recent development of high efficiency vircators like the SINUS-7 of S. A. Kitsanov et al. reported 5% efficiency with /spl sim/1 GW output, and K. Yatsui et al. reported a coaxial vircator, similar to M. Kristiansen´s design, capable of /spl sim/10% beam-to-microwave efficiency. The former has a modulating gap beside the anode, the latter relies on opposite facing electron beams to boost efficiency. The difference in terms of electron beam dynamics is the focus of the study. The MAGIC code is used to simulate both structures, and their performance is compared under an identical assumption of cathode performance. The effect of system impedance on efficiency and output intensity is addressed.