Mean flows and the onset of chaos in large-cell convection.

Numerical simulations of two-dimensional model equations show that a coupling between amplitude and vertical-vorticity fields allows chaotic flows near the onset of Rayleigh-Benard convection in large aspect ratio domains. In cylindrical cells, mean flows arising from this coupling lead to a chaotic nucleation of dislocations that is remarkably similar to a mechanism recently observed in convection experiments.