Study On Cavity Electron Cyclotron Maser

Being high power resources of millimeter-wave radiation, based on electron cyclotron maser, gyrotron has been pay much respect in the world for vast applications in many areas such as plasma heating, linear accelerators, millimeter wave radar, communications, electronic countermeasure and so forth. Specifically in twenty years later, there was much developments on gyrotron. At home, in the later of 1970s, Prof. Liu Shenggang began the research on electron cyclotron maser, and later, the group leaded by Prof. Li Hongfu has done much research work on gyrotron also, and successfully developed a first Ka band third harmonic gyrotron oscillator with a permanent magnet system. And later, theyhave began the research on a kind of gyrotron amplifier-gyroklystron. Thedetail study on the interaction between the electron beam and standing wave of complex cavity gyrotron with gradual transition and gyroklystron has been done in this dissertation, supported by the pre-study important items "the study on 8mm third harmonic gyrotron with a permanent magnet system" and "the study on 8mm high power gyroklystron". The main works of this dissertation are listed as following:1. The study on the RF distribution of the complex cavity with gradual transition is presented, in which the multi-modes coupling are taken into account. The influences of the TM modes on the RF distribution of the complex cavity are analyzed in detail. Further more, The influences of the angle of the section with gradual transition on the RF distribution of the complex cavity are analyzed in detail.2. Based on the self-consistent nonlinear theory of complex cavity gyrotron with gradual transition, a simulation code of self-consistent nonlinear beam-wave interaction has been made, in which the multiple modes interaction with an electron beam and the mode coupling are taken into account. The interaction between the electron beam and Hsn-H521 RF field for third-harmonicgyrotron is simulated. The influences of the thickness and the velocity spread and the velocity ratio of the electron beam and the fluctuation of the magnetic field and the technologic errors of complex cavity on the multi-modes interaction with an electron beam are analyzed.3. Based on the simulation, a 8mm third harmonic complex cavity gyrotron with gradual transition, to which a permanent magnet system could be used, is designed and tested.4. A nonlinear theoretical model for two-cavity gyroklystron is established. The analytic method on the beam-wave interaction in input cavity and output cavity is studied. And the simulation on the nonlinear beam-wave interaction of two-cavity gyroklystron is made. The influences of the drift length and beam voltage and current and the velocity ratio of the electron beam and et al. on efficiency and gain are analyzed in detail.5. A nonlinear theoretical model for multi-cavity gyroklystron is established. The analytic method on the beam-wave interaction in mid-cavity (buncher) is studied. And the simulation on the nonlinear beam-wave interaction of multi-cavity gyroklystron is made. The influences of more factors on efficiency and gain in multi-cavity gyroklystron are analyzed, comparing with in two-cavity gyroklystron.