  Within the limits of the large-N_c approximation (with N_c the number of
colors), we establish the high-energy behaviour of the diffractive and
inclusive cross-sections for deep inelastic scattering at fixed impact
parameter. We demonstrate that for sufficiently high energies and up to very
large values of Q^2, well above the proton average saturation momentum <Q_s^2>,
the cross-sections are dominated by dense fluctuations in the target
wavefunction, that is, by the relatively rare gluon configurations which are at
saturation on the resolution scale Q^2 of the virtual photon. This has
important physical consequences, like the emergence of a new, diffusive,
scaling, which replaces the `geometric scaling' property characteristic of the
mean field approximation. To establish this, we shall rely on a dipole version
of the Good-Walker formula for diffraction (that we shall derive here in the
context of DIS), together with the high-energy estimates for the dipole
scattering amplitudes which follow from the recently established evolution
equations with Pomeron loops and include the relevant fluctuations. We also
find that, as a consequence of fluctuations, the diffractive cross-section at
high energy is dominated by the elastic scattering of the quark-antiquark
component of the virtual photon, up to relatively large virtualities Q^2 >>
<Q_s^2>.
