Halo formation and chaos in space-charge-dominated beams

Halo formation is an important issue in the design of advanced high-current, high-power particle accelerators in wide applications such as high-energy physics research, tritium production, and heavy ion fusion as well as in the development of advanced radiation sources and high-power, high-resolution radar. In this paper, the mechanisms of halo formation and chaotic particle motion are explored for space-charge-dominated beams propagating through a linear, periodic focusing channel provided by a periodic solenoidal magnetic field. For root-mean-squared (rms) matched beams with nonuniform density profiles, it is shown in a test-particle model that nonlinearities in the self field forces not only can result in chaotic particle motion but also can cause a halo to develop