Electric field lines of charged particle in a helical undulator

Abstract

One of the devices for generating circularly polarized radiation is a helical undulator in which a relativistic charged particle moves along a helical trajectory. In this paper, the spatial distribution of the electromagnetic field produced by such a particle is analyzed using electric field lines. The equations of electric field lines, which, due to the presence of curvature and torsion in the trajectory are precisely solved. A special algorithm for erasing invisible parts of the lines has been developed to represent the lines in space. Several remarkable features of the field picture are revealed, in particular, the hard component of the radiation is concentrated in the plane orthogonal to the undulator axis and passing through the position of the particle at the current moment of time.