  With a classical ensemble model that including electron correlations during
the whole ionization process, we investigated strong-field sequential double
ionization of Ar by elliptically polarized pulses at the quantitative level.
The experimentally observed intensity-dependent three-band or four-band
structures in the ion momentum distributions are well reproduced with this
classical model. More importantly, the experimentally measured ionization time
of the second electrons [A. N. Pfeiffer et al., Nature Phys. 7, 428 (2011)],
which can not be predicted by the standard independent-electron model, is
quantitatively reproduced by this fully classical correlated model. The success
of our work encourages classical description and interpretation of the complex
multi-electron effects in strong field ionization where nonperturbative quantum
approaches are currently not feasible.
