Spatial Synchronization of TE-Modes in a Slit-Type Gyrotron Cavity
R. M. Rozental, Yu. Yu. Danilov, A. N. Leontyev, A. M. Malkin, Dmitry Shchegolkov, В. П. Тараканов
Abstract
We propose a variant of a slitted cavity for gyrotrons based on spatial synchronization of TE-type modes with azimuthal indexes equal to multiples of the slit number and close eigenfrequencies. A simplified theory of such a cavity is presented demonstrating its basic properties. High selectivity of the novel cavity was confirmed by 3-D PIC simulation of a 0.3-THz gyrotron energized by a helical electron beam with an energy of 500 keV and a current of 2 kA. This simulation demonstrates that, using the slit-type cavity, stable single-frequency operation at TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6,4</sub> –TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12,2</sub> mode combined with an output power of more than 80 MW and an efficiency of about 8%. The same arrangement with a conventional solid-wall cavity demonstrates no single-frequency regimes at all.