D. Garzella

Dynamic filling factor in the Super-ACO free electron laser

Abstract Here, the Free Electron Laser evolution before the start-up from the spontaneous radiation of an undulator, is considered. This analysis is carried on through the dynamical behaviour of the Filling-factor, representing the transverse overlap between the light pulse and the electron bunch. In such a framework, the gain optimization before the laser start-up is presented and more generally applied to low-gain storage-ring free electron lasers, such as on Super-ACO.

Self-consistent harmonic generation in storage ring FELs

We explore the self-induced harmonic generation in Storage Ring Optical Klystron (SR OK) FEL devices. We use a numerical code which accounts for the SR OK FEL longitudinal dynamics, includes the laser pulse propagation, and gives an accurate image ofthe phenomenology ofinstabilities associated with the laser–electron beam interplay. The coherent harmonic generation evolution is developed using the bunching parameter theory. The analysis we develop yields the turn-by-turn evolution ofthe harmonics and provides an accurate physical insight into their dependence on the intracavity laser power. The results obtained with this code are considered with mainly a Q-switched configuration evaluated for an Elettra-like facility. r 2003 Elsevier Science B.V. All rights reserved.

Super-ACO FEL oscillation with longitudinal to transverse coupled beam dynamics

The Super-ACO storage ring Free Electron Laser (FEL) has been operated using an alternative operating point characterized by a non-zero dispersion function in the undulator straight section, linking the transverse motion of the electrons to the energy spread, and by a low momentum compaction factor. The longitudinal to transverse coupled electron beam motion induces a modified dynamics of the Super-ACO FEL. The FEL characteristics, such as the FEL power, pulse duration and spectral width are presented and analyzed in terms of storage ring FEL dynamics.

LASER HEATING AND MICROWAVE INSTABILITY IN THE SUPER-ACO FEL

Abstract In a storage ring FEL, both laser heating and microwave instability concour to define the equilibrium state of the longitudinal beam dynamics. Their competitive interplay can be studied by analysing the equilibrium laser power. Preliminary results of the laser power analysis and longitudinal dynamics characterization - carried out at the Super-ACO storage ring FEL - are hereby presented. PACS codes: 41.60. Cr; 29.20. Dh