CHAOTIC ELECTRON TRAJECTORIES IN A CIRCULAR FREE ELECTRON LASER
在环型自由电子激光器中电子运动的混沌特性

The motion of a relativistic electron is analyzed in the field configuration consisting of a circular wiggler magnetic field, an axial magnetic field, and the equilibrium self-electric and self-magnetic fields produced by the non-neutral electron beam. By generating Poincare surface-of-section maps, it is shown that when the self-fields are strong enough, the electron motions become chaotic. Although the realistic circular wiggler field makes the equations of electron motion nonintegrable as the self-fields do, the effect of self-fields to cause the chaoticity is stronger than the wiggler field. The axial magnetic field can suppress the occurrence of chaoticity.