Electroproduction of e+e--pairs in external field

The process of the electron-positron pair production accompanying the movement of the electron in the constant magnetic field is considered in detail. Particular attention is paid to the spectral distribution of produced particles. Assuming the step-like behaviour of the field on the boundary the contribution of boundary photons to the process under consideration is calculated. Simple approximate formulae for the probability of magnetic bremsstrahlung radiation and photoproduction of pairs in the external field are given