Millimeter Wave Gyroklystron Amplifier Self-consistent Nonlinear Theory And Simulation

As a novel millimeter-wave coherent radiation source with high-power capability, high-efficiency and moderate bandwidth advantages, gyroklystron amplifiers have received a great deal of attention in recent years for a variety of applications such as high-power millimeter radar, electromagnetic countermeasure (ECM), communications, precision guidance, material processing, plasma heating, and a new generation of particle accelerators and so on.The interaction between electron beam and high-frequency electromagnetic field directly determines electron efficiency and operation performance of the vacuum electron device, so the study of the beam-wave interaction is currently one of the most extensive projects and also the most important content of the device research.In this dissertation, the self-consistent nonlinear equations of the electron beam-wave interaction in the gyroklystron amplifier are formed on the basis of the self-consistent nonlinear theory and the calculation program of the self-consistent nonlinear electron beam-wave interaction GKLSC is independently developed on the Microsoft Developer Studio Fortran platform. The electron beam-wave interaction of the gyroklystron amplifier is thoroughly studied and analyzed by the self-consistent nonlinear program. Our work mainly consists of the simulation analyses of the beam-wave interaction in the fundamental two-cavity gyroklystron amplifier, fundamental three-cavity gyroklystron amplifier, second harmonic two-cavity gyroklystron amplifier and second harmonic three-cavity gyroklystron amplifier. We expounded the physical picture and characteristics of the beam-wave interaction in the fundamental and second harmonic device, and analyzed the influence of the device structure and operating parameters including electron beam voltage, electron beam current, velocity pitch, normalized guiding center, magnetic field etc. on output power, electron efficiency and gain. In addition, we also studied the characteristic of the output cavity in the gyroklystron amplifier by the self-consistent nonlinear program.PIC (Particle-in-cell) software has inherent advantages in the simulation of the time-evolution process and the beam-wave interaction. At the same time, PIC software can simulate some actual processes of the beam-wave interaction because of taking on the optimum arithmetic and complete function modules. On the basis of the device designed by theself-consistent nonlinear program, we studied the fundamental three-cavity gyroklystron amplifier, second harmonic two-cavity gyroklystron amplifier and second harmonic three-cavity gyroklystron amplifier by means of the PIC software, and discussed the influence of the device structure and various operating parameters on the device performance. In addition, the quality factor and eigen-frequency of the output cavity are also calculated with the high frequency software HFSS.In the process of studying the influence of structure parameters and various operating parameters on the electron efficiency and gain in the different gyroklystron amplifier, the simulation results of the self-consistent nonlinear program GKLSC are compared with that of the PIC software. The trends of the simulation results are the same to a degree and the variation regularity of electron efficiency as a function of some operating parameters is accordant. By contrast with the results of the second harmonic gyroklystron amplifier, the simulation results of the self-consistent nonlinear program GKLSC are more in accordance with that of PIC software for the fundamental gyroklystron amplifier.By the compare of the simulation results, the self-consistent nonlinear program GKLSC, as being a fast simulation code of the beam-wave interaction can be used as the preliminary design tool and provide the preliminary parameters for the PIC software in the process of designing the gyroklystron amplifier. So the time of designing device is greatly reduced. Furthermore, it can also improve the understanding of the beam-wave interaction. This work has important significance for the study of the millimeter wave gyroklystron amplifier.