Physical mechanism of beam halo-chaos formation for high-current proton beam in a periodic-focusing channels and a nonlinear control strategy

<正> The physical mechanism of the halo-chaos formation for a high intensity proton beam in a periodic-focusing channel is analyzed using the transfer matrix theory and a qualitative analysis method. Particles-in-cell simulations are further used to explore the mechanism of the beam halo-chaos formation, which concerns not only with the nonlinear effect of the beam space charge but also with the transverse energy exchange between the particles and the particle-core, as well as the chaos generated by the nonlinear resonance overlap. A nonlinear control method is proposed for controlling the halo-chaos. Simulation results show that the method is effective. Some potential applications of the halo-chaos control in experiments are discussed.