Spontaneous braking effect at electron scattering in the field of a plane electromagnetic wave

A general relativistic expression for the amplitude of spontaneous electron bremsstrahlung on the Coulomb centre in the field of a plane electromagnetic wave of arbitrary intensity is obtained. Expressions for spontaneous photon frequencies at which the amplitude goes into infinity which is connected with virtual electron yield onto mass shell are given. In the field of intensities and frequencies of the external field eta=ea1/m << 1 and xi=ea1/#betta#' << m/#betta#' >> 1 a general expression for nonresonance radiation cross section is obtained as well as resonance cross section in the absence of interference. It is shown, that in the nonrelativistic case at electron scattering at wide angles the resonance differential cross section may by several orders of the value exceed the usual bremsstrahlung cross section