Temporal and spectral evolution of a storage ring FEL source: experimental results on Super-ACO and new theoretical approach

Because of the complex interaction in a storage ring FEL system (SRFEL + storage ring), SRFELs show various phenomena. Conventional theoretical models, such as the super-modes model, can not treat the dynamic behavior of the SRFELs, or do not contain spectral effects. In this paper, a new simulation model is presented, which enables the study of temporal and spectral behavior of a SRFEL. Novel is that this model starts from the spontaneous emission spectrum, which is specially important for small gain FELs. The simulation results are compared with the experimental observations of the Super-ACO FEL. We have also used the simulation code to study the response of the laser to perturbation on the beam. These results provide meaningful aspects for designing new storage rings.