Study of non-sequential double ionization of Ar and Ar+

Abstract

The non-sequential (NS) double ionization of Ar and Ar+is studied using a semiclassical model. The Ar2+ /Ar+ andAr3+ /Ar2+ratios are obtained and compared with experimental results. As a comparison, theNS double ionization of Ne is also studied. The analysis shows that the neweffect—suppression of multiple ionization of atomic ions in intense ultrashort laserpulses—found in experiments (Greenwood et al 2002 Phys. Rev. Lett. 88 233001)should be interpreted as enhancement of the triple ionization of a neutral target.