Beam dynamics in high luminosity e+e- factories

The e⁺e^- factories achieve their high luminosity by storing a large current in many bunches. A number of collective effects, some of them new, strongly influence the dynamics of the beams in this very high current regime. Backgrounds of electrons (due to multipacting or photoemission) cause collective instabilities and emittance dilution. Heavy beam loading and ion clearing gaps in the bunch pattern have a strong effect on the longitudinal dynamics. The large number of bunches,in the factories requires crossing angle collisions in some machines, coupling the longitudinal and transverse dynamics. Parasitic collisions are present, wigglers may be used to manipulate the emittance and radiation damping rates, and the electron and positron beams in asymmetric B-factories have unequal parameters. We review the wealth of recent beam dynamics observations made at the e⁺e^- factories