Halo Formation in 3-D Bunches with Different Phase Space Distributions

We recently constructed, analytically and numerically, a new class of self-consistent 6-D phase space stationary distributions [1], which allowed us to study the halo development mechanism without being obscured by the effect of beam redistribution. In this paper we consider nonstationary distributions and study how the halo characteristics compare with those obtained using the stationary distribution. In contrast to bunches with a large aspect ratio we find that the effect of coupling between the r and z planes is especially important as the bunch shape becomes more spherical.