2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/93453The first order quantum correction to the power of spontaneous radiation of electrons in an arbitrary two-component periodic magnetic field was obtained. The phenomenon of selfpolarization of the spin of electrons in a process of spontaneous radiation was also studied. By electron's motion in a spiral magnetic undulator, the quantitative characteristics of selfpolarization (the polarization degree and the relaxation time) are different from corresponding ones in synchrotron radiation. The limiting cases of near-axis and ultrarelativistic approximation were considered.18 pages, AMS-LATEX, no figures. Int. J. Mod. Phys. B (to sub.)Quantum Physicstext