Tunnel above-threshold ionization of multicharge ions: photoelectron relativistic distributions and effect of gradient stabilization

摘要

Spatial distributions of above-threshold photoelectrons produced during the tunnel ionization of multicharge ions by laser radiation of relativistic intensity are theoretically investigated. It is shown that an essential modification of these distributions should be due to simultaneous manifestation of relativistic effects and Coulomb interaction of photoelectron with its parent ion. For short laser pulse, the distribution becomes composed of two peaks. Positions of these peaks depend on the radiation intensity and ellipticity, and also, on the charge of the parent ion. The last dependence can be used for the control of ionization process of mullielectron atoms. A new mechanism has been found that increases the multicharge ion stability in regard to ionization by superintense ultrashort pump pulse. The gradient forces on the trailing edge of the pulse able to compensate the relativistic drift of photoelectron. And due to Coulomb attraction, it is possible to electron be captured back to the closed orbit after the pump pulse is over.