High power microwave generation by relativistic backward wave oscillator

Abstract

In this paper, a high power relativistic backward wave oscillator (BWO) experiment is reported. A 230 kV, 2 kA, and 150 ns relativistic electron beam source is developed using a Marx generator. The beam is then injected into a hollow rippled wall metallic cylindrical tube that forms a slow wave structure (SWS). A BWO is a slow wave structure in the form of a rippled wall wave-guide and is used as a source of high power microwave generation when excited by a relativistic electron beam (REB). The beam is guided using an axial pulsed magnetic field having, the duration 1 ms and strength being 1.0 Tesla, respectively. This field is generated by discharge of a capacitor bank into a solenoidal coil. A synchronization circuit ensures the generation of the electron beam at the instant when the axial magnetic field attains its peak value. The electron beam interacts with the SWS waveguide modes and generates microwaves due to Cherenkov interaction. Estimated power of ~2 MW in TM01 mode is observed.