Chaotic Mixing in Charged-Particle-Beams and Galaxies

摘要

Rapid irreversible dynamics is a practical concern in producing high-brightness charged-particle beams. Time scales of irreversible processes place constraints on methods for compensating against degradation of beam quality caused by, for example, space charge or coherent synchrotron radiation. Compensation must be fast compared to active irreversible processes, and this affects the choice and configuration of the associated hardware. A beam bunch with space charge comprises an N-body system with typically 3N degrees of freedom. Orbits in the nonlinear space-charge force may be chaotic, especially in a nonequilibrium beam. Through phase mixing, an initially localized ensemble of chaotic orbits will grow exponentially and eventually diffuse through its accessible phase space, reaching an invariant distribution.