Amlitude and phase control of superradiation pulses by the magnetic bias of saturated ferrite

To provide controllable shortening of the cathode voltage rise time in two channels of superradiative oscillators, ferrite-loaded sections of a coaxial transmission line with a bias magnetic field were used. Saturation of the ferrites in the longitudinal direction was provided by a dc magnetic field of 50 kA/m. A nonlinear line of length 30 cm was tested. It was found that a nonlinear line not only reduces the voltage rise time, but also changes the time delay to the arrival of the voltage pulse at a tubular explosive-emission cathode. Subgigawatt X-band microwave pulses of 1 ns FWHM were produced by two relativistic BWOs operating at a low magnetic field (about 0.5 T) in corrugated slow-wave structures. The cathode voltage and the e-beam current were 330 kV and 3 kA, respectively. Conditions for coherent summation of the power radiated in vacuum by two channels have been found.