  Dynamical localization prevents driven atomic systems from fast fragmentation
by hampering the excitation process. We present numerical simulations within a
collinear model of microwave-driven helium Rydberg atoms and prove that
dynamical localization survives the impact of electron-electron interaction,
even for doubly excited states in the presence of fast autoionization. We
conclude that the effect of electron-electron repulsion on localization can be
described by an appropriate rescaling of the atomic level density and of the
external field with the strength of the interaction.
