Zonal flow as pattern formation

Zonal flows and pattern formation

The general aspects of zonal flow physics, their formation, damping and interplay with quasi two dimensional turbulence are explained in the context of magnetized plasmas and quasi-geostrophic fluids with an emphasis on formation and selection of spatial patterns. General features of zonal flows as they appear in planetary atmospheres, rotating convection experiments and fusion plasmas are revi...

Zonal flow formation in the presence of ambient mean shear

Secondary instability in drift wave turbulence as a mechanism for zonal flow and avalanche formation

The article reports on recent developments in the theory of secondary instability in drift–ion temperature gradient turbulence. Specifically, the article explores secondary instability as a mechanism for zonal flow generation, transport barrier dynamics and avalanche formation. These in turn are related to the space–time statistics of the drift wave induced flux, the scaling of transport with c...

Subcritical Pattern Formation in Granular Flow

We study a minimal model for the flow of granular material on a conveyor belt consisting of a staircase-like array of K vertically vibrated compartments. Applying a steady inflow rate Q to the top compartment, we determine the maximum value Qcr(K) for which a continuous flow through the system is possible. BeyondQcr(K), which depends on the vibration strength and the dimensions of the system, a...

Pattern formation by bacteria-driven flow.

Some marine bacterial species form mucosal layers, called veils, on sulfidic marine sediment. The bacteria attached to this veil actively swim and exert force on the surrounding fluid. The bacteria can break free of the veil and swim, chemotacting back to the veil. Over time the veil forms holes arranged in a hexagonal pattern. Motivated by this system, we present a simplified model to describe...