Nonsequential multiple ionization in intense laser pulses: interpretation of ion momentum distributions within the classical 'rescattering' model

The classical 'rescattering' model is used to give an interpretation of ion momentum distributions for multiple ionization of atoms in intense fs lase r pulses. Kinematical constraints for the ion momenta derived from simple c lassical considerations reproduce the positions of the maxima observed in e xperimental momentum distributions of Ne2+ and Ne3+ ions. Based on these co nstraints we present a first prediction on the principle structure of diffe rential ion momentum distributions for multiple ionization. We show that di fferent ionization channels can be characterized by their kinematics, leadi ng to specific ion momentum distributions. A qualitative analysis of the in tensity dependence is also given.