Regensburg 2019 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 15: Pattern Formation

DY 15.6: Talk

Tuesday, April 2, 2019, 11:15–11:30, H3

Pattern formation in salt playa — •Jana Lasser — Max Planck Institut für Dynamik und Selbstorganisation, Göttingen

Salt pans are geological sinks where evaporation outweighs precipitation. As a result, a continuous salt crust forms, which expresses iconinc hexagonal ridge patterns with a diameter of roughly one meter. We model the process driving the emergence of these patterns as result of an instability in a dynamical process, taking place in the ground below the patterns: Here, the subsurface is composed of a porous medium saturated with salty water. As water evaporates through the surface, a salinity gradient builds below the surface and is prone to a buoyancy-driven convective instability. With this advection-diffusion model, we can explain the onset of convection as well as the length scale of the patterns. We show evidence from experiments, numerical simulations and direct field observations, confirming that convection takes place in the underground, and that convection cells are co-located with the patterns visible on the surface.