Suppression of surface field enhancement to improve power capacity of RBWO

The influence of field enhancement factors on the power capacity of relativistic backward wave oscillators is preliminarily investigated in the paper. Under the conditions of strong field, positive asperity and burr on the surface of high frequency structures will lead to field electron emission and RF breakdown, which can further generate plasma and lead to pulse shortening and reduction of power limit. By precisely polishing the surface of a kind of X band RBWO, the surface roughness can be reduced to less than 1/40 of the initial value, where the power limit will increase by at least 25%.