A big power THz wave resonant cavity

The resonant electro-magnetic field confined in a cylindrical cavity filled with a smaller coaxial cylindrical electron beam is analyzed theoretically, and the eigenfrequency equations of the fundamental mode of the resonant electro-magnetic field confined in the cavity are educed and calculated by the software Matlab. The calculated results show that the fundamental mode frequency of the electro-magnetic field in the cavity changes with the plasma resonant frequency of the electron beam, and when the plasma resonant frequency of the electron beam approaches to the fundamental mode frequency of the resonant electro-magnetic field in the cavity, the fundamental mode frequency of the resonant electro-magnetic field will make a jump. In the calculational model, the cavity of diameter 6mm fills with an electron beam of diameter 2mm and the cavity of diameter 6mm fills with an electron beam of diameter 4mm and the density of electron beam increases continuously, then the fundamental mode frequency of the resonant electro-magnetic field in the cavity experiences a few times of jumps and steps up to the THz wave frequency that higher than 300GHz.