CHAOTIC BEHAVIOR AND HALO FORMATION FROM 2D SPACE-CHARGE DOMINATED BEAMS

In a previous paper [J.-M. Lagniel, Nucl. Instr. and Meth. A 345 (1994 ) 46], it has been shown that space-charge dominated beams can induce chaotic behaviour of the particle trajectories. This phenomenon, which leads to halo formation has now been studied with a more realistic mo del than the simple one used in the previous paper. A 2D beam core wit h uniform density and finite emittance travels through a focusing chan nel made up of quadrupoles and thin lenses simulating RF gap defocusin g effects. Simulation results with and without synchrobetatron couplin g are discussed.