ABSTRACT
A generalization of the Hènon map is discussed; such a model arises in a natural way from the extrapolation of the multipolar errors of the superconducting dipoles of the planned Large Hadron Collider in CERN. The symmetries of the map in the resonant case are studied; a qualitative analysis of the phase space structure is given. The dynamic aperture of this model is not well defined, since far from the origin one recovers a quasi linear regime; the computation of the dynamic aperture of the truncated map in its dependence on the truncation order is performed: this allows to give an estimate of the highest significant multipole which should be included in tracking simulations.
