Libration-driven inertial waves and mean zonal flows in spherical shells

Driven inertial waves in spherical Couette flow.

Dynamo action in the cores of planets and stars gives rise to their magnetic fields. We explore spherical Couette flows in liquid sodium as a laboratory model of the Earth’s core. Below, we image various spatiotemporal magnetic-field modes present in spherical Couette flows. Our apparatus is comprised of two independently driven rotating spheres, radii 20 and 60 cm, with sodium filling the gap ...

Experimental study of libration-driven zonal flows in non-axisymmetric containers

Orbital dynamics that lead to longitudinal libration of celestial bodies also result in an elliptically deformed equatorial core-mantle boundary. The non-axisymmetry of the boundary leads to a topographic coupling between the assumed rigid mantle and the underlying low viscosity fluid. The present experimental study investigates the effect of non axisymmetric boundaries on the zonal flow driven...

Libration-induced mean flow in a spherical shell

Zonal flows in a mean-field solar dynamo model

Cyclic variations are observed in the solar differential rotation profile. The 11 year periodicity of these zonal shear flows (often referred to as “torsional oscillations”) is consistent with the idea that they are driven by the Lorentz forces that are associated with the large-scale solar dynamo. This suggests that these flows may be able to provide indirect observational evidence that can be...

Generation of zonal flows by Rossby waves in the atmosphere

A novel mechanism for the short-scale Rossby waves interacting with long-scale zonal flows in the Earth’s atmosphere is studied. The model is based on the parametric excitation of convective cells by finite amplitude Rossby waves. We use a set of coupled equations describing the nonlinear interaction of Rossby waves and zonal flows which admits the excitation of zonal flows. The generation of s...