Stabilizing the intensity for a Hamiltonian model of the FEL

Romain Bachelard (1, 2) , Cristel Chandre (1, 2) , Duccio Fanelli (3) , Xavier Leoncini (1, 2) , Michel Vittot (1, 2)

1 CPT - Centre de Physique Théorique - UMR 6207
2 CPT - Centre de Physique Théorique - UMR 7332
3 dip. energetica

The intensity of an electromagnetic wave interacting self-consistently with a beam of charged particles, as in a Free Electron Laser, displays large oscillations due to an aggregate of particles, called the macro-particle. In this article, we propose a strategy to stabilize the intensity by destabilizing the macro-particle. This strategy involves the study of the linear stability of a specific periodic orbit of a mean-field model. As a control parameter - the amplitude of an external wave - is varied, a bifurcation occur in the system which has drastic effects on the self-consistent dynamics, and in particular, on the macro-particle. We show how to obtain an appropriate tuning of the control parameter which is able to strongly decrease the oscillations of the intensity without reducing its mean-value.

Mots clés: Wave/particle interactions; Control of chaos; Hamiltonian approach

Domaines: Dynamique Chaotique [nlin.CD]

Romain Bachelard, Cristel Chandre, Duccio Fanelli, Xavier Leoncini, Michel Vittot. Stabilizing the intensity for a Hamiltonian model of the FEL. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008, 593 (1-2), pp.94-97. ⟨10.1016/j.nima.2008.04.050⟩. ⟨hal-00292542⟩