Energy transfer in nonequilibrium space-charge-dominated beams

Space-charge modes similar to those observed in recent experiments appear i n simulations of nonequilibrium charged particle beams with anisotropy. The modes couple degrees of freedom, causing energy transfer and equipartition ing without halo formation in just a few betatron wavelengths. The rate dep ends on a single free parameter quantifying the space-charge intensity of t he final state. Traditional stability analyses are shown not to apply to hi gh-intensity laboratory beams originating with a large perturbation from eq uilibrium.