Chaotic behavior and halo development in the transverse dynamics of heavy-ion beams

This paper reviews results obtained from recent analytical and numerical investigations of chaotic behavior and halo development induced by charge density inhomogeneities in the transverse dynamics of heavy-ion beams. In particular, a test-particle model is used to investigate the charged-particle dynamics in an intense matched heavy-ion beam with non-uniform density profile propagating through an alternating-gradient quadrupole magnetic field in the space-charge-dominated regime. It is shown that self-field non-linearities due to transvere non-uniformities in the beam density not only can result in chaotic ion motion but also can cause halo formation. For heavy-ion fusion applications, these results indicate that accurate density profile control is critical in preventing heavy-ion beams from developing halos.