Subfemtosecond study of the hypersatellite-satellite cascade in ‘‘hollow’’ atoms

The behavior of slow, fully stripped ${\mathrm{Ar}}^{18+}$ ions near metallic surfaces has been studied. These ions capture, while touching the surface, a large number of electrons in outermost shells, leading to the formation of ‘‘hollow’’ atoms. The timing of the hypersatellite-satellite cascade filling the double K-vacancy states is studied in this paper by using the internal clock constituted by the ‘‘tops’’ of the temporal sequence filling stepwise the L shell of the ion.