Double-electron above threshold ionization of helium

We present calculations of intense-field multiphoton ionization processes i n helium at XUV wavelengths. The calculations are obtained from a full-dime nsional integration of the two-electron time-dependent Schrodinger equation . A momentum-space analysis of the ionizing two-electron wavepacket reveals the existence of double-electron above threshold ionization (DATI). In mom entum-space two distinct forms of DAITI are resolved, namely non-sequential and sequential. In non-sequential DATI correlated electrons resonantly abs orb and share energy in integer units of h omega (laser).