Split or unsplit electron beams?

Non-linear effects have become increasingly relevant in modern circular particle accelerators, and in recent years a change of paradigm has appeared, the attitude towards nonlinear effects having shifted from fighting them to exploiting them with the goal of devising new beam manipulations, such as the splitting of the beam in the transverse phase space by crossing a stable resonance. In the field of hadron accelerators, well-established operational techniques based on nonlinear effects exist, whereas for the case of synchrotron light sources these new techniques are only beginning their way into the field. In this paper, we discuss novel techniques aimed at providing split beams in synchrotron light sources that are obtained by using stable islands in the transverse phase space or unsplit beams with AC dipoles to generate periodic closed orbits. The results of detailed numerical simulations, which support the proposed methods, are presented and discussed in this paper, together with possible applications.