Evolution of the distribution function and radiation spectrum for electrons in a magnetic field

The evolution of a system of electrons with a given initial distribution in an external magnetic field is considered. An equation describing the evolu tion of the electron distribution function in a uniform magnetic field is d erived for the case of arbitrarily relativistic electrons, and an exact sol ution to this equation is found. Asymptotics of this solution corresponding to the cases of synchrotron radiation and relativistic dipole radiation ar e calculated, and the evolution of the radiation spectra for these limiting cases is analyzed. The curvature of the magnetic field lines is taken into account phenomenologically, which demonstrates the presence of an exponent ial dependence in the case of synchrotron radiation. (C) 2000 MAIK "Nauka/I nterperiodica".