Studies of a two-section backward wave oscillator for efficient high power microwave generation

Summary form only given. The effects of a nonuniform amplitude slow-wave structure are being studied using the University of New Mexico´s high-power relativistic backward wave oscillator (BWO) driven by a SINUS-6 repetitively pulsed electron beam accelerator. The BWO produces a 12-ns microwave pulse with a peak power of 600 MW at 9.6 GHz. The ripples within the slow-wave structure have a constant period of 15 cm, but their amplitudes were arranged in two sections to increase the efficient microwave radiation. In the first half of the slow-wave structure the ripples have a small amplitude while in the second half the ripples have a much larger amplitude. Different configurations of the two-stage slow-wave structure were used and compared with the total output of microwave power. The changes to the slow-wave structure were compared with MAGIC computer simulations, which suggest that the first section of shallow ripples prebunches the electron beam and results in greater efficiency of microwave generation in the second section.