  Electron-electron correlation effects play an instrumental role in our
understanding of sequential (SDI) and non-sequential double ionization (NSDI)
mechanisms. Here, we present a theoretical study of NSDI driven by
plasmonic-enhanced spatial inhomogeneous fields. By numerically solving the
time-dependent Schr\"odinger equation for a linear reduced model of He and a
double-electron time-evolution probability analysis, we provide evidence for
the enhancement effects in NSDI showing that the double ionization yield at
lower laser peak intensities is increased due to the inhomogeneity of the laser
field. Furthermore, our quantum mechanical model, as well as classical
trajectory Monte Carlo simulations, show that inhomogeneous fields are a useful
tool for splitting the binary and recoil processes in the rescattering
scenario.
