Bremsstrahlung in laser-assisted scattering

The process of spontaneous radiation accompanying the scattering of a charged particle by a center of force is studied under conditions in which the scattering takes place in an intense, low-frequency laser field. Approximations are developed which provide expressions for both the amplitude and the total rate for spontaneous bremsstrahlung in the presence of the external field, given in terms of the physical (onshell) amplitude for bremsstrahlung in the absence of the field. Of particular interest is the effect of the external field on the radiation probability when there is a narrow resonance in the field-free scattering