Production of ultra-short high-power microwave pulses in Čerenkov backward-wave systems (review)

The article presents a review of works (mainly, of experimental ones) on production of subgigawatt and gigawatt microwave pulses of extremely short duration (5-7 RF periods) using backward-wave systems fed with nanosecond and subnanosecond high-current electron beams produced by compact accelerators. Theoretical approaches to the generation process (which is essentially non-steady-state) are briefly summarized. Using the effect of spatial accumulation of energy in a short running microwave pulse allows production of pulses with peak power notably higher then the driving electron beam power. Compact microwave sources developed for operation in the Ka-band and X-band are described. Special attention is given to the issue of high pulse repetition frequency operation of the sources.