Simulation of superradiant free electron lasers

Abstract It has been suggested that slippage effects in a single-pass free electron laser can generate an output signal near the electron beam tail with a peak amplitude many times greater than the expected saturated value [1]. The growth of such “superradiant” pulses in a helical-wiggler FEL is characterized here using 1-D and 2-D numerical simulations. The 1-D calculations show the effects of detuning, energy spread, and the axial current distribution on superradiant pulses, while preliminary 2-D simulations illustrate the effects of betatron motion and the radial structure of the electron beam.