Polarization of electrons in storage rings by circularly polarized electromagnetic waves

The electron (positron) polarization process in storage rings is studied when irradiating the beam by a colliding electromagnetic wave. The effect arises due to the dependence of radiation friction in the wave field on the spin and the spin motion coupling with the orbital motion in the field of a storage ring. The degree of equilibrium polarization and the relaxation time are found. A numerical example for the case of laser polarization is presented. (Auth.)