In the series of works (refs.[4,6,19]) the diffusion created by
a chaotic motion in a chaotic layer was studied numerically and theoretically.
It was shown that the diffusion rate in a coupled degree of freedom
with frequency decays with
in the exponential
way
where
is the width of the chaotic layer and
is some weak function of the
parameters of the layer. This result shows that the modulational diffusion
is in some sense similar to the Arnold diffusion but on the other
side it gives much stronger diffusion rate due to large values of
.