Vortex Radiation from Relativistic Electrons

Abstract

An electron in circular motion radiates an electromagnetic wave possessing a helical wave-front and carrying angular momentum other than spin. I discuss the theoretical background of this process and give an intuitive explanation. I also show some evidences from experiments at a synchrotron light source. Radiation from an electron in circular motion is the basis of various important radiation processes, such as cyclotron/synchrotron radiations, Thomson/Compton scatterings of circular polarized light and so on. This finding indicates that vortex radiations in the VUV, X-rays and gamma-rays can be produced by accelerator based technologies. Moreover, it indicates that vortex photons can be naturally created in various situations in the universe.