A Research On Key Technology Of MW-Level Gyroklystron

As a high power millimeter wave source,Gyroklystron has important applications in military and scientific research fields,such as microwave radar,electronic countermeasures and electronic interference,microwave communication,high-power microwave rejection weapon equipment and controllable thermonuclear fusion.With the increasing demand of microwave power source,especially in high power,broadband,high reliability,researches on megawatt gyrotron have been carried out overseas in recent years.Due to its high efficiency of wave-beam interaction and bandwidth,gyroklystron has its unique advantages in MW-level output.Up to now,MW-level gyroklystron whose interaction efficiency is about 40% requires a input electron-beam voltage over 100 KV with the input current over 30 A.Under the condition of high voltage and high current electron-beam input,it is a difficult issue for MW-level gyroklystron to ensure the bunching effect of electron-beam,the stability of beam-wave interaction,the power capacity of output cavity and the competition of suppression mode.In this thesis,the design of gyroklystron resonator cavities and the theoretical analysis of beam-wave interaction are studied in order to design high frequency system.A nonlinear numerical program of gyroklystron is compiled based on beam-wave interaction.Results are compared and the parameters are optimized with CST Microwave Studio.Specific research as follows:1.Briefly introduce the theoretical basis of gyrotron-electron cyclotron maser.Basic structure,development history,application and prospect of MW-level gyroklystron and gyrotron are introduced;2.According to basic theoretical analysis of gyroklystron resonant cavity,resonance frequency and Q factor of resonant cavities are calculated and optimized by CST Microwave Studio.The influence of structural parameters on resonance frequency and Q factor of the cavity is studied.The input cavity,the bunching cavity,the output cavity and the output structure are designed;3.In view of theoretical analysis on beam-wave interaction,the evolution formula of high frequency field and the formula of electron motion of the beam-wave interaction in gyroklystron are derived.Combined with the actual process of the beam-wave interaction,the numerical calculation flow is designed and compiled in Mat Lab.4.The stability of gyroklystron is analyzed.Optimize the calculation progress of numerical calculation.The high frequency system of gyroklystron and the angular modulation of electron-beam are designed by numerical calculation.The effects of electron beam parameters,guide magnetic field parameters,input frequency and input power on beam-wave interaction efficiency and output power are analyzed by CST Microwave Studio.The results of nonlinear numerical calculation are compared with those calculated in CST Microwave Studio.The design of MW-level gyroklystron is completed.5.Summarize the completed assignment and project the further assignment of this thesis.Overall,this thesis shows the process of beam-wave interaction in nonlinear numerical calculation program according to the operating principle of gyroklystron.With the help of both nonlinear numerical calculation program and simulation software,this thesis completes the design of a MW-level gyroklystron.The fundamental harmonic three-cavity MW-level gyroklystron,which works in the Ka-band,has 36 GHz central frequency,an output power of 2.8MW,an electron beam efficiency of 38%,a bandwidth of 500 MHz and a gain of 44 d B.