Modulational diffusion

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 $\omega$ decays with $\omega$ in the exponential way $D(\omega) \sim exp(-C\omega/{\Delta \omega})$ where $\Delta \omega$ is the width of the chaotic layer and $C$ 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 $\Delta \omega$.