A Novel Multi-Aperture-Distribution Based Cold Cathode Driven Plasma Assisted BWO

We introduce a novel multi-aperture r-θ configuration on a plasma assisted cold cathode to generate a high current density electron beam simultaneously with high energy and high fill factor. The generation of an electron beam with all three characteristics is a critical challenge in designing an electron beam source for efficient RF generation from BWO. The optimization of the beam emitting apertures distribution is carried out using 3D PIC software, VSim. An electron beam source based on the cold cathode optimized design with 17 circular apertures of dia 1 mm each is developed. The developed electron beam source is utilized inside the plasma assisted BWO. The efficiency of the cold cathode-driven BWO is found to be 16.5 % with an RF peak power of 12 kW at an applied gap voltage of ~20 kV. The measured frequency of the generated RF radiation is ranging from 10-11.75 GHz.