Is There a Common Thread to Layering in Atmospheres, Oceans and Plasmas?

Coordinators: Guilhem Dif-Pradalier, Pascale Garaud, David W.Hughes, and Bruce Sutherland

This conference has been cancelled. The associated program will be held online. Those interested in the online program should apply via the link on the program webpage.

A fascinating and surprising phenomenon that can occur in fluid and plasma turbulence is the spontaneous formation of arrays of layers in which material properties such as density adopt a so-called “staircase” structure. The most striking examples are potential vorticity staircases in planetary atmospheres, and thermohaline staircases in the oceans. Theoretical considerations suggest that layering also plays an important role in stellar interiors (particularly through various double-diffusive processes) and in fusion confinement devices (the so-called E x B staircase). Understanding the phenomenon of layering is, therefore, not only of intrinsic scientific interest (e.g., is there a common thread to layering in these very different contexts?), but is also crucial for an accurate description of turbulent transport in, for example, models of large-scale ocean flow, the evolution of stellar interiors and confinement in tokamaks.

Although there has been considerable progress in understanding staircase formation in all of these separate fields, chiefly through numerical simulations, important questions relevant to both physical understanding and mathematical modelling remain to be answered. By convening experts across physics and mathematics, this conference will rapidly review and seek common underlying principles related to layering in diverse physical systems, highlight frontier challenges and advanced techniques in this area, and identify salient problems to be addressed in the near future.