STABILITY AND HALO FORMATION IN AXISYMMETRIC INTENSE BEAMS

Beam stability and halo formation in high-intensity axi-symmetric 2D beams in a uniform focusing channel are analyzed using particle-in-cell simulations. The tune de-pression- mismatch space is explored for the uniform (KV) distribution of the particle transverse-phase-space density, as well as for more realistic ones (in particular, the water-bag distribution), to determine the stability limits and halo parameters. The numerical results show an agreement with predictions of the analytical model for halo formation [1].