COMPLEXITY ANALYSIS AND CONTROL STRATEGY FOR BEAM HALO-CHAOS IN ADS

Beam halo-chaos in high-current accelerators has become a key concerned issue because it can cause excessive radioactivity from the accelerators therefore significantly limits their applications in industry, medicine, and national defense. This article reviews the complexity of accelerator driven clean nuclear power system (ADS) as well as the associate physical mechanism for beam halo-chaos formation in high-intensity proton linear accelerator. Notably, some general engineering methods for chaos control have been developed in recent years, but they are generally unsuccessful for beam halo-chaos suppression due to many technical constraints. In this article, some of these technical problems are addressed. Particles-in-Cell (PIC) simulations are described, for exploring the nature of beam halo-chaos formation. Some efficient nonlinear control methods, including wavelet function feedback control, are reported for beam halo-chaos suppression. PIC simulations show that after control is applied to the initial proton beam with water bag or full Gauss distributions, the beam halo strength factor is quickly reduced to zero, and other statistical physical quantities of beam halo-chaos are also doubly reduced. These performed PIC simulation results demonstrate that the developed methods are very effective for halo-chaos suppression. Potential applications of the beam halo-chaos control methods are finally discussed.