Growth of the energy spread due to the radiative interaction in a short electron bunch moving in an undulator

This paper presents investigations of the longitudinal radiative force in an electron bunch moving in an undulator (wiggler). An analytical solution is obtained for a Gaussian longitudinal bunch profile. Radiative interaction of the particles in an intense microbunch induces a correlated energy spread in the electron beam. Numerical estimates presented in this paper show that this effect can be important for free electron lasers.