  D.I.S. at small Bjorken $x$ is considered within the dipole cascade
formalism. The running coupling in impact parameter space is introduced in
order to parametrize effects that arise from emission of large size dipoles.
This results in a new evolution equation for the dipole cascade. Strong
coupling effects are analyzed after transforming the evolution equation in
Borel ($b$) space. The Borel singularities of the solution are discussed first
for the universal part of the dipole cascade and then for the specific process
of D.I.S. at small $x$. In the latter case the leading infrared renormalon is
at $b=1/\beta_0$ indicating the presence of $1/Q^2$ power corrections for the
small-$x$ structure functions.

High Energy Physics - Phenomenology