Cyclotron Backward-wave Tube

Until now, cyclotron devices have an irreplaceable place in the high power field. Among them, Gyro-BWO has important application value and good prospect in the high power microwave sources, and the international attention is paid to its theoretical research and project implementation. Gyro-BWO has the advantages of continuous tuning, broadband, and so on. However, it also has its unavoidable drawbacks:First, the axial velocity is scattered, causing work unstable and affecting interaction efficiency. Secondly, low work efficiency. Electron beam gets better and better with the length of interaction, but high-frequency field increases reversely. This makes the energy exchange efficiency low.This article makes a detailed analysis and calculation about the high frequency structure of Ku band Gyro-BWO, according to linear and nonlinear theory. The research is done through theoretical analysis, numerical calculation, programming optimization and analog simulation. The main content includes:First, studying amply on the cyclotron linear theory and choosing appropriate parameters to account the parameters about backward wave. Through the coupling coefficient contrast of several candidate modes, the operating mode TE01 is selected. Then, the cyclotron linear theory is deduced and any waveguide cyclotron maser dispersion equation is derived; Next, choosing suitable electron beam parameters, applied magnetic field Bo and others to educe the circular waveguide cyclotron maser dispersion equation, and conducting the programming calculation; Finally, getting the dispersion curve, linear gain, starting length, starting frequency and other relative parameters.Second, doing a detailed research and reduction on the cyclotron nonlinear theory. At first, waveguide field equations are given. By derivation and conversion, the relation of high frequency field and electron beam harmonic current areobtained; Afterwards, changing the coordinate, using cyclotron center coordinate to describe electromic motion equation; And then, exporting the expression of high frequency field force and the high frequency equation which is expressed by potential function; Then, analyzing the distribution of electron kinetic energy along the mutual effect currents; At last, nonlinear first order differential equations is elicited.Third, educing the Gyro-BWO beam-wave self-consistent equations by integrating cyclotron nonlinear first order differential equations. Selecting thirty-two electrons as macro-electron to study the beam-wave interaction. Firstly, obtaining the relation between starting length and starting current. Then figuring out the variation trend of Gyro-BWO work efficiency. Next, studying the amplitude change of beam-wave interaction and the variation trend of macro-electron phase.Four, analyzing and contrasting according to the results of linear and nonlinear theory, and giving an account by combining related simulations. Firstly, comparing two theories' starting length and starting current, then comparing their variation trend of amplitude; finally, summarizing the two theoretical results.