Simulation Study of High-Power Annular Beam Extended Interaction Device

In order to develop high power millimeter wave and terahertz radiation sources, the simulation research of high-current over-mode annular beam extended interaction device is carried out in this paper. By embedding a concentric metal cylinder with periodic array holes in a circular waveguide with periodic radial grooves, the radial electric field distribution of TM 02 -like mode is optimized. The annular electron beam interacts with $TM_{02}$ mode between the cylinder and the waveguide. In the output section, the microwave is coupled to extractor in TM 01 mode through a circular aperture in the axial direction. The applied voltage is 28.6 kV, the current is 1 A, the inside radius of the electron beam is 2.54 mm, the outside radius is 2.75 mm, and the current density is $28.65\ \mathrm{A}/\text{cm}^{2}$ . The particle in cell simulation results show that the device can generate 9.38 kW at 0.1 THz, and the beam-wave interaction efficiency is 32.81%.