Stabilization window and attosecond pulse train production at atom ionization in superintense laser field

Abstract

We present the results of numerical experiments on a two-dimensional model atom driven by a high-intense laser pulse. The electron wave-packet behavior is studied in a range of laser parameters corresponding to the dynamic stabilization regime. Wave packet localization in this regime with arbitrary laser polarizations is shown to manifest itself macroscopically by high-order harmonic production in the form of long trains of attosecond pulses. Calculations for the sub-relativistic regime of laser-atom interaction are carried out without making the dipole approximation in order to take into account the Lorentz force effect in wave packet evolution. The transition from polychotomy to the magnetic-field-induced drifting at very high laser intensities is documented which results in the electron delocalization. As a consequence, the intensity dependence of the atomic survival probability as well as that of the efficiency of high-order harmonic production possess a wide "stabilization window" followed by an abrupt drop because of the magnetic field effect.