Transverse space-charge modes in non-equilibrium beams

Successful operation of a Heavy Ion Fusion driver requires knowledge of how the beam responds to various perturbations from equilibrium. Recently, sim ulations and experiments have verified predictions that space-charge-domina ted beams can carry waves, observable as modulations in the particle densit y and temperature. Self-consistent simulations using the particle-in-cell c ode WARP explore the evolution and scaling of space charge modes, both in l inear and circular machines. Examples of phenomena where these collective m odes play a critical role are provided. In circular focusing arrays, the mo des resonate when driven by lattice errors, at frequencies which depend on the space charge intensity. Collective modes are shown to lead to emittance exchange and energy equipartitioning in an anisotropic system. Scaling rel ations are determined for some of these effects. (C) 2001 Elsevier Science B.V, All rights reserved.