Generation And Transmission Of Intense Relativistic Annular Electron Beam Without Guiding Magnetic Field

As far as most of the high power microwave source is concerned, the mechanism of microwave generation is to make use of the interaction between beam electrons and microwave, during which the energy of the electron beam transfers to the microwave, and the power of the microwaves generated. Comparing with the solid electron beam, the annular electron beam has some advantages that the space-charge effects and the electron potential energy is less. So many high power microwave sources use intense relativistic annular electron beam to interact with microwave. This paper tries to realize the generation and transmission of the intense relativistic annular electron beam without the guiding magnetic field, in order to reducing the system's volume, weight and the consuming of the energy.Firstly, the transmission of foil-focused relativistic annular electron beam in coaxial cylindrical waveguide is studied. The distributions of the electric potential and the electric filed in coaxial excursion space are given by calculating Poisson equation via numerical calculation. And the space-charge-limited current of the foil-focused relativistic annular electron beam transporting in coaxial cylindrical waveguide is given. The equilibrium of the envelope electrons is given by analyzing the forces on the envelope electrons. And the track of the envelope electrons is given in terms of its equation of motion. Consequently, when the parameters of the electron beam are known, we can rectify the parameters of the excursion space according to the tracks of the envelope electrons, so that the foil-focused relativistic annular electron beam can transport in coaxial cylindrical waveguide stably.The space-charge-limited current of the planar diode is given approximately when the diode generate annular electron beam. It provides the gist for design of the diode's parameters and the experiment of generating annular electron beam. The Pierce-like cathode is designed on the theoretical analysis combined with the particle simulation, which can generate intense relativistic annular electron beam without guiding magnetic field. And its feasibility is validated by experiment.A faraday cup is designed to measure the current of the intense relativistic annular electron beam, whose radius and thickness are alterable. So its validity range is wide.