Spin effects in the interaction of atoms with intense and high-frequency laser fields in the non-relativistic regime

We present numerical simulations of an atom interacting with very intense, high-frequency and linearly polarized laser fields in the non-relativistic regime, taking into account the coupling of the spin of the electron with t he magnetic field. The Pauli equation is solved for a two-dimensional atom model, retaining the space dependence of the electric and magnetic fields. The short-wavelength domain is explored extensively, showing new non-dipole effects that depend on the spin degree of freedom. An analytical non-dipol e model is developed to calculate approximately the time evolution of the P auli wavefunction, that works accurately in this domain.