ENHANCEMENT OF PARTICLE TRAPPING IN THE FREE ELECTRON LASER

The saturated dynamics of a Single Pass Free Electron Laser is here considered within a simplified mean field approach. A method is proposed to increase the size of the macro-particle. This approach is based on the reconstruction of invariant tori of the dynamics of test particles. To this aim a dedicated control term is derived, the latter acting as a small apt perturbation of the system dynamics. Implications of these findings are discussed in relation to the optimization of the laser source.