Beam Wave Interaction Simulation Of Second Harmonic Terahertz Gyrotron

Terahertz wave is between infrared and millimeter-wave, and it not only has strongabsorption characteristic and dispersion characteristic, but also has the advantages ofhigh-resolution, ultra-wideband, low radiation, high-speed and strong penetrating, soterahertz wave has been become a research hotspot. Terahertz technology is the key toproduce terahertz electromagnetic waves, thus terahertz sources of high power and highefficiency are the foundation of the terahertz technology can be widely applied. So far,the gyrotron is the highest radiation power device in the terahertz band, so the gyrotronis favored by countries all over the world.Gyrotron has superior performance in terms of amplification and oscillation in themillimeter wave band and sub-millimeter wave, so it has important applications in radar,communications, electronic countermeasures, controlled thermonuclear fusion andhigh-power microwave weapons. At present, research work of gyrotron in the UnitedStates, Russia and Germany on behalf of the international level.As with traditional microwave tubes, beam wave interaction is bound to beanalyzed in research gyrotron work. Electron bunching and energy exchange ofelectronic and electromagnetic waves are in the process of wave interaction, and thestrong and weak interactions directly affect the efficiency and power of the gyrotron, soit is very critical to the simulation of wave interaction. Based on the linear theory andnonlinear self-consistent theory of gyrotron, the design and research of a0.42THzgyrotron operating at the Second Harmonic was presented in the thesis by the support ofthe national science and technology projects. The main work of this thesis is listed asfollowing:1. Based on the theory of gyrotron, the design of a0.42THz gyrotron operating atthe Second Harmonic and the analysis on RF distribution of the high frequencystructure are presented. The characteristic of RF structure of the0.42THz secondharmonic gyrotron is researched by using the simulation software.2. The linear theory of the0.42THz gyrotron operating at the Second Harmonic isresearched, mainly including the analysis of dispersion equation, the selection of the electron beam radius and the analysis of start-up current, and it Pave the way for thenumerical simulation of beam wave interaction.3. The nonlinear self-consistent theory of gyrotron is researched, andhigh-frequency field equations and electron motion equations are derived. The physicalquantities are normalized, and it is prepared for the numerical simulation of beam waveinteraction.4. Through a calculation simulation code of beam wave interaction designed byourselves, a self-consistent nonlinear simulation on the0.42THz second harmonicgyrotron is presented. The influences of the velocity ratio of the electron beam, themagnetic field coefficient, current, the electron beam radius and voltage under beamwave interaction are analyzed. Finally, the design parameters and electric parameters ofa0.42THz gyrotron operating at the Second Harmonic are summarized.