Controlling chaotic behavior of the equilibrium electrons by simultaneous using of two guiding fields in a free-electron laser with an electromagnetic-wave wiggler

Abstract

In the present paper the effects of the combination of the axial-guide magnetic field and the ion-channel guiding on the chaotic trajectories in a free-electron laser with electromagnetic-wave wiggler have been considered. It is shown that the simultaneous using of the two guiding fields in the certain conditions causes chaotic behavior in the electron motion. It is also illustrated that the chaotic trajectories decrease as the ion-channel density or the strength of the axial magnetic field increases. The transition from the chaotic trajectories to regular trajectories, occurs at a special ion-channel density, ω−it, or a particular amount of the strength of the axial magnetic field, at. Furthermore numerically calculation shows that the normalized ion-channel frequency of the transition, ω−it, reduces by increasing the axial magnetic field. Also ω−i increase causes the trajectories to be regular at the weaker at. The electron motion has been altered significantly by the self-fields effects. It is demonstrated that, the self-fields cause a decrement in the chaotic trajectories. This is in contrast to the idealized helical wiggler FEL with the axial magnetic field guiding.