Spin Modification And Medium Effects Of Radiation From A Relativistic Electron

This dissertation on radiation from a relativistic electron focuses on two topics, the spin modification and the medium effect. As the basis for the investigations, a comprehensive review on the classical radiation theory is made. The Jefimenko formulas and their generalization, as well as Heaviside-Feynman expression for fields generated by moving charge and dipole, are covered. A general expression for the spectral-angular distribution of the radiation energy from a relativistic electron with magnetic moment is obtained. Hence the spectral distribution of radiation in two polarizations from a relativistic synchronous electron is calculated including the modification of electron’s magnetic moment. The relationship between the polarizations of the synchronous electrons and the radiation fields, which suggests getting information about spin polarization of electron beam from measuring the polarization of the synchrotron radiation, is provided. The general expression for spectral-angular distribution of the radiation emitted by a charged particle moving in exterior medium is derived from Maxwell equations in medium. On this expression which includes a Fourier type integral, the essential role of stationary phase points in Cherenkov effect is analyzed and stated definitely. Therefore for the calculation of synchrotron-Cherenkov radiation from charged particle moving in curved orbit the stationary phase method is proposed, which is more versatile and applicable compared with the exiting two kinds treatments in literatures. Consequently the spectral distribution of synchrotron-Cherenkov radiation is calculated by stationary phase method, and the result indicates the spectrum of synchrotron-Cherenkov radiation in directions near critical angle is quite different from that in the vicinity of the orbit plane.