Periodic Dielectric Cerenkov Maser Research

The main part of this paper is follow: Firstly make a rough explanation about Cerenkov effect, by using of PIC program, when macro charged particle traveling at superluminal velocities pass through dielectric, the radiation graph about radiation has been achieved. After that found the physical mechanism about the interaction between wave and relativistic electron beam. Making use of self-consistent linear field theory, the threedimensional perturbation of electron affected by the perturbed electromagnetic fields is generally discussed. The interactions of wave to the conventional relativistic electron beam in the dielectric Cerenkov maser i. e annular electron beam and solid electron beam, are discussed in detail. The dispersion equations and wave growth rates corresponding to the two relativistic electron beams are derived. So by analysis of this dispersion equation the dispersive curve has been drawn, also found the linear wave growth. According to the cross point of waveguide mode and the electron beam mode, so called synchronous point, thus operation frequency can be found. And the effects of the accelerate voltage, electron beam current and relativistic dielectric constant on the linear wave growth rate are presented. At the condition, with and without considering the effect of the longitudinal guide magnetic field respectively, the effect of three dimensional perturbed velocities and three dimensional perturbed current densities on the beam wave interaction of dielectric Cerenkowmaser is analysed. Result show when decreasing the thickness of dielectric, the output frequency will increasing, but at the same time the output power will go down sharply. Through the changed dielectric structure, the output frequency can be enhanced without lost the output power, that lead to the appearance of periodic dielectric Cerenkov maser.Secondly cording to the analysis of periodic dielectric Cerenkov maser, by using of equivalence theory, periodic dielectric Cerenkov maser has been considered as flat anisotropic dielectric. So by using the wave equation in anisotropic dielectric and the matched condition, the periodic dielectric Cerenkov maser dispersion equation, dispersion curve, and linear wave growth are derived. By comparing periodic dielectric parameter with flat dielectric parameter, two important result have been found. First at the same input condition, the curve of periodic dielectric maser is much more higher than fiat dielectric maser, even higher than later's higher order mode. So higher output frequency can be achieved without lost output power. Second the output power and output frequency will be changed Corresponding to theε_z andε_r (same as to adjust the percentage of dielectric area) So by adjust the width of dielectric film make it is possible to achieve high frequency microwave output.Thirdly through the way of cold cavity character particle simulation, we can see the transmission characteristic. Similarly through the way of hot cavity character particle simulation, the microwave generate process can be documented in detail, this documented results can testify the correction of former theory.