Many-body effects in multiply charged ion formation in a superstrong laser field

We report the numerical calculations for the multiple ionization of rubidium in a strong laser field. We consider multiply charged ion formation and take into account some of the many-body effects, i.e., the inelastic tunneling effect, the collective tunneling, and m relaxation of an ionic core. In the case of strong fields, with intensities in excess of 10(17) W/cm(2), the free motion of a photoelectron is affected by the magnetic component of the laser field. Because of this, the formation of multiply charged ions as a result of a rescattering process becomes improbable. We present our findings for Rb10+ and Rb11+ ions, where a significant contribution of collective tunneling was revealed, which was not observed in the weaker fields previously investigated [A. S. Kornev, E. B. Tulenko, and B. A. Zon, Phys. Rev. A 68, 043414 (2003); Phys. Rev. A 69, 065401 (2004)].