Electromagnetic Radiation Source Based On Cherenkov Radiation

Cherenkov radiation is a kind of free electron radiation, which often been used as Cherenkov detector, Cherenkov wakefield accelerator, as well as Cherenkov free-electron laser(FEL). Cherenkov mechanism has been used as a radiation source working in terahertz regime in 2009 by A.M. Cook, who comes from the University of California, his team have observed a radiation with operating frequency 0.37 THz, and its power reaches 150 KW with a pulse length of 60 ps. Compared to Cherenkov free electron laser, this kind of source has the same ability to reach high power level, and its structure may be more simple. In this thesis, coherent Cherenkov radiation source has been studied. The main work of the thesis as follows:(1)The dispersion characteristics of a cylindrical dielectric-lined waveguide which is excited by Relativistic electron has been studied. Detailed discussion of the factors affecting the dispersion characteristics of the structure has been made, such as the vacuum zone thickness, the thickness of the dielectric layer, the relative dielectric permittivity of the dielectric layer, and the emit voltage of the electron bunch.(2)The radiation power of each mode of cylindrical dielectric-lined waveguide has been studied, when the structure was excited by single electron bunch. By adjusting the parameters of the waveguide structure, and the root-mean-square length of the electron bunch makes the structure work on 01 TM mode, and the theory was validated by the means of numerical analysis and particle-in-cell simulation.(3)Resonant excitation of coherent Cherenkov radiation in cylindrical dielectric-lined waveguide by periodic electron bunch has been studied. By setting the harmonic frequency of the bunch reduplication, we can enhance mode 02 TM and inhibit mode01 TM, thus we can use the waveguide with larger size to get the same operating frequency, the radiation power can be designed higher also.(4)The dispersion characteristics of planar dielectric-loaded structure has been studied. Theoretical analysis of the dispersion characteristics of the structure has been made and a preliminary discussion of the characteristics of structure when it being stimulated by particle simulations, laying a foundation for the work to be undertaken.(5)According to the law of the theoretical analysis, a coherent Cherenkov radiation wakefield terahertz radiation source with 1THz operating frequency has been designed. Optimizing the design parameters through theoretical analysis and particle-in-cell simulation, a radiation source with 1THz operating frequency, 01 TM mode, are available, the output power of the radiation reaches 200 KW.