# Spectral diffusion in wave turbulence systems with nonlocal interaction.

Wednesday 04, 09:00

Sergey Nazarenko

CNRS/UniversitĂ© CĂ´te d'Azur

Often in wave turbulence systems, the picture of the classical local energy cascade breaks down due to concentration of energy at the largest scales. This is a classical wave analogue of the Bose-Einstein condensation phenomenon which renders the Kolmogorov-Zakharov spectra irrelevant. In these situations, the dominant wave resonances involve motions with large space and time scale separations, which yields to reduced descriptions via the diffusion-type evolution in the k-space. I will review previous works applying these ideas for the three-wave internal waves and the Rossby waves, and report on our recent work on the four-wave systems, the gravity water waves and the MMT waves. I will empasize important differences between the concave up and concave down dispersion relations in terms of dominance of the angular or radia spectrall diffusion.