Dynamics of zonal flows in planetary interiors and core-mantle interactions

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The focus of my research is on the dynamics of fluid planetary interiors and on core-mantle interactions in terrestrial planets. These are key elements in the evolution of planets and explain why, within our solar system alone, each planet has had a markedly different history. In this proposal, my research group will address using advanced computational models topics that range from understanding variations in the length of the Earth's day through to complex fluid behavior seen in the atmospheres of the giant planets. Planetary rotation is the dominant dynamical influence on flows inside planets. Flows in rapidly rotating planets exhibit a remarkable (and unintuitive) behavior: they tend to have no velocity variation in the direction parallel to the rotation axis. A displaced parcel of fluid will entrain with it every parcels above and below in a vertical column: the flow behaves as if it is only two-dimensional (2D). In my research group, we exploit this feature and simulate planetary flows using a 2D model of the dynamics. This allows us to study more turbulent regimes. In this research proposal, we will apply these ideas to simulate the zonal jets that are observed on Jupiter. We also apply this concept to simulate flows in the Earth's core, more specifically to study a class of flow that consists of differential motion between co-centric cylinders aligned with the rotation axis. Flows in Earth's core also interact with its solid boundaries at the top (mantle) and bottom (inner core). These interactions include electromagnetic (EM) coupling; one of my projects is to investigate the role that non-uniform EM coupling at the core-mantle boundary may have on the geometry of the magnetic field and its time variations observed at the Earth's surface. In addition, fluid-solid interactions produce changes in the rotation rates of the inner core and mantle: the latter are observed as changes in the length of day (LOD). One of my projects proposes to test different scenarios of core-mantle interactions with a goal to identify the nature of the force responsible for the changes in the LOD over the past 100 years.