Fluid and Vlasov Stability of Intense Ion Beams in Periodic Channels

Transverse beam behaviour of an intense beam through long periodic systems is reviewed critically. In view of the uncertainty about the proper choice of a distribution function the applicability of a hydrodynamical approach is discussed. Starting from a laminar beam, structure resonances and their shift by finite temperature are introduced as hydrodynamic features. The Vlasov treatment brings in additional structure resonances and entirely new features, like velocity space instabilities, if a loss-cone distribution (for instance K-V distribution) is chosen. The relevance of these instabilities for beam transport considerations is briefly discussed.