Structure Design And Optimization Of Gyrotron Electron Optical System

The working frequency of the traditional microwave tube determines the size of the high frequency structure.When the traditional microwave tube develops to a higher frequency,the size must be smaller and smaller.Due to the small size,greatly limits the power capacity of the microwave tube.Gyrotron is a new type of electric vacuum device based on the principle of stimulated emission of free electrons.Because of the different working principle,the high frequency structure of gyrotron is not limited by frequency,and Gyrotron has a broad prospect in the field of millimeter wave radar,electronic warfare,high power microwave weapons,controlled thermonuclear fusion and other high-power microwave applications.Magnetron injection electron gun(MIG),gyrotron collector and superconducting magnet make up the electron optical system of gyrotron.Magnetron injection electron gun(MIG)is one of the key components of gyrotron,and its performance directly affects the output power and efficiency of the gyrotron.In recent years,one of the main development directions of high power microwave devices is high power and high frequency.In order to meet the gyrotron for higher output power requirements,besides improving the input voltage of electron beam and the interaction efficiency,we can improve and optimize the gyrotron magnetron injection gun(MIG)to generate the appropriate speed ratio,low orbit electron beam velocity spread.The electrons are scattered over the collector under the guidance of the magnetic field.For some reasons,electronic will appear concentrated concentration,scattered area is too small and so on.It's will lead to serious heat collection in a certain area of a collector,which will cause damage to collector and seriously affect the service life of the whole Gyrotron.In this thesis,the electron optics system of gyrotron is studied in detail.The main work of this paper is as follows:Based on the basic theory of electromagnetic field and the theory of electrodynamics,the basic methods of the design and calculation of electron optical system are described.The basic working principle of magnetron injection gun is explained and the design flow and optimization method of the magnetron injection gun(MIG)is introduced.The paper introduce the basic calculation principle of software EGUN,Magic,and CST used in electron gun,a single anode magnetron injection electron gun for 140 GHz high power gyrotron was successfully designed for ITER scheme.A single anode magnetron injection electron gun with a W band gyrotron is designed;In this paper,the realization method of the defocusing of the gyrotron collector system is studied,and the defocus system of the defocusing collector is optimized by software simulation.