What we have learned from 3D andr, z intense-beam simulations using the WARP code

A multi-dimensional discrete-particle simulation code, WARP, and its application to heavy-ion fusion beams is described. The code's 3D package combines features of an accelerator code and a particle-in-cell plasma simulation, and can efficiently track beams through many lattice elements and around bends. The code'sr, z package allows one to follow beams over very long times and models the accelerating module impedances. A number of applications are presented. These have led to an improved understanding of: beam equilibria, and the approach to equilibrium; longitudinal beam dynamics and stability; electrostatic quadrupole (ESQ) injector aberrations; bending and recirculation of space-charge-dominated beams; and the drift-compression process. The code is being used for accelerator design, as well as for theoretical investigations.