Chaotic nature of the super-ACO FEL

The response of the Free Electron Laser (FEL) to an external perturbation can be studied by applying a laser gain modulation. When its frequency is close to the laser resonance one, a non-linear gain variation of the Super-ACO storage ring FEL can lead to a chaotic dynamic behaviour of the laser macro-temporal structure. At a fixed frequency of the modulation, and increasing its amplitude, the systematic analysis of the macro-temporal structure of the laser, shows that chaos appears between two periodic regimes. The attractors, i.e. the phase-space representation of the macro-temporal structure, characterize the regime as periodic, quasi-periodic, or chaotic. The bifurcation scheme evolves with the frequency of the modulation. The experimental macro-temporal sequences can be reproduced by LAS the numerical empirical code developed in the Super-ACO FEL group. Here the comparison between the experimental and numerical results obtained on the non-linear dynamics of the Super-ACO FEL is presented.