Experiments on Convection and Turbulence in Earth's Core

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Olson 0105238 This project consists of a series laboratory fluid dynamical experiments designed to simulate processes that are important in the generation of the geomagnetic field in Earth's liquid outer core. One set of experiments will be conducted in rotating hemispherical shells of fluid, and are intended to model thermal convection in the self-gravitating, rotating, spherical geometry of the core. The purpose here is to delineate those characteristics of rotating spherical shell convection that can be used to interpret seismic and geomagnetic images of the core. A second series of laboratory experiments will be conducted on thermochemical convection in solidifying gallium-indium alloys, with and without the influences of rotation and externally applied magnetic fields. The gallium-indium alloy is analogous to the iron-rich alloy of the outer core, and the solidification represents the growth of Earth's solid inner core. These experiments are designed to test the assumptions of the gravitationally powered dynamo model, which is widely regarded as the most likely energy source for the geodynamo, and to determine the properties of turbulent fluid motion in the environment of the outer core.