| This dissertation is mainly about the transit radiation of the electron beam passing through the gap with the random standing wave electric field. In order to satisfy the requirement of the task, the feasibility of generation of more than 1 GW high power microwave in X-band using the transit radiation oscillator based on the transit effect is studied.Starting from the velocity modulation and bunch of the electron beam passing through an infinite small gap, the transit effect of electron beam passing through the gap with the random standing wave electric field is studied, and the analytic formulas of electron load conductance are derived and the beam-wave energy interchange is discussed. The small signal theory of the transit effect in the gap with the random standing wave electric field is built up. As an example, the transit effect of electron beam passing through the N-cavity gap with the π mode standing wave electric field which are constant distribution (N=l,2,3,4,5,6,7) and sinusoid distribution (N=l,2,3,4,5) in each cavity is obtained. In order to compare with the results of the literature[12], the analytic formulas of the relationship between FN(θ) and the transit angle 9 are derived. The calculation results of FN (θ) are good agreement with the results the literature [12].A new type of resonant in X-band is given. The eigenfrequencies and eigenfunctions of TM mode of three four and five-cavity resonant is studied. The self modulation of the working modes which are 2π/4 mode in three-cavity, 3π/5 mode in four-cavity, 4π/6 mode in five-cavity is simulated by PIC code Magic. The transit effect of all modes of three four and five-cavity resonant is calculated by code Mathcad and Matlab.We investigated the interaction between the electron beam and the eigenmode in the resonant by the 2.5 dimensional particle simulation code. The simulation indicated that the electron beam can interact with the eigenmode in resonant. A X-band five-cavity TRO is designed. With the voltage 760kV,the current 6kA and the magnetic field 2.6T in the simulation, it's output power is about 1.2GW. The arithmetic of generating the mesh of column coordinate of two-dimension is introduced. Based on this arithmetic, the high frequency characteristics of five-cavity with open boundary is calculated by the code written in Fortran language. Then the transit effect of five modes of five-cavity with open boundary is also calculated using code Mathcad and Matlab. The results show that the working mode of five-cavity transit tube oscillator is 3π/6 mode, and the analysis of the theory are in goodagreement with the simulation results.A X-band six-cavity TRO is studied. With the voltage 760kV\ 6kA and the magnetic field 2.6T in the simulation, output power is about 1.5GW is obtained, and interaction efficiency is 31%. A noveland high accurate numerical synthetic technique is presented for determining the high frequency characteristics of six-cavity with open boundary. The numerical method based on the coupling of the finite difference method in time domain with the discrete fast Fourier transform is applied to calculate the first four eigenfrequencies and eigenfunctions of the six-cavity with open boundary. The absorbing boundary condition for TEM wave is tested numerically, and it is applied to writing the code. The cold testing of the cavity is done and the results are good agreement with the numerical results. The first four eigenfrequencies and eigenfunctions of the close cavity are calculated as well. Then the transit effect of them is analyzed by Mathcad and Matlab as well. The results of calculation show that the unstable modes are 9.3384GHz and 8.3496GHz, but the working mode is 9.3384GHz.The simulation shows that the frequency-spectrum characteristic of the TRO is related with its output results, so the frequency-spectrum diagnosis is an important work for the X-band TRO research .The frequency synthesis technique is used for the frequency-spectrum diagnosis. We discussed the configurations of...
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