The Effect of Ion-Channel Guiding on the Chaotic Electron Trajectories in a Free Electron Laser

Abstract

It has been confirmed that when the equilibrium self-fields were taken into account, the motion of an electron in a helical wiggler with axial magnetic field may be chaotic. In this paper, the effect of an ion-channel guiding on the chaotic electron trajectories is analyzed. It is shown that the ion-channel guiding may modify the chaotic electron trajectories. It is also found that when the parameter e, i.e. e = ω pb/4ω 2 c , is increased, the density of the ion-channel guiding, i.e. αi = ω 2 pi/4ω 2 c , must be increased to keep the modification of the chaotic motion. The chaotic trajectories for constant parameter e and increased density of the ion-channel guiding are presented. Numerical calculations are used to find the intersection between steady state group I and group II and resonance curves. Poincare surface-ofsection maps are generated to demonstrate the chaotic electron trajectories with axial magnetic field and its modification in the presence of an ion-channel guiding.