High-power THz range planar gyrotrons with transverse energy extraction

For increasing the integral power of short wavelength gyrotrons it is suggested to use the planar geometry of interaction space with a sheet electron beam and transverse (with respect to electron translation velocity) energy extraction. The advantage of such a scheme in comparison with conventional cylindrical gyrotrons is diffraction mode selection over the open transverse coordinate in combination with effective radiation out coupling that essentially reduces ohmic losses. Simulations of planar gyrotron demonstrate feasibility of achieving the radiation power up to several hundred kilowatts for frequency 1 THz. Possibility of further increasing radiation power with increasing electron beam width is shown by smoothly tapering of the gap between waveguide plates to increase wave group velocity at periphery (similar to unstable resonators in optics).