Numerical/Experimental Canonical Models of Geophysical and Astrophysical Flows

Adolfo Ribeiro, UCLA, Earth Planetary and Earth Science, LOS ANGELES, CA, United States, Jean-Luc Guermond, Texas A&M University, Mathematics, College Station, TX, United States and Jonathan M Aurnou, University of California Los Angeles, Department of Earth, Planetary, and Space Sciences, Los Angeles, United States

Contact First Author: Adolfo Ribeiro; ribeiro@ess.ucla.edu

Previously Published Material: Title: "Canonical Models of Geophysical and Astrophysical Flows:Turbulent Convection Experiments in Liquid Metals" Authors: A.Ribeiro, J-L Guermond, J.M Aurnouunder revision, Metals Paper

Abstract ID#: 35957

 

English Abstract:
System-scale magnetic fields are observed to develop in galaxies, stars, planets, moons, and even asteroids. In all these systems, magnetohydrodynamic dynamo action occurs via the conversion of the kinetic energy of flowing electrically-conductive fluids into magnetic field energy. Generated by the motion of the electrically-conductive fluid, dynamo fields typically evolve on length and time scales related to the underlying flows. \\

Present-day numerical models do not yet model dynamo action in liquid metals with a thermal Prandtl number, $Pr <1$ and a magnetic Prandtl number, $Pm \ll 1$. Metal dynamo simulations should become possible, though, within the next decade. In order then to better understand the turbulent convection phenomena occurring in geophysical or astrophysical fluids and next-generation numerical models thereof, we present here canonical, end-member examples of thermally-driven convection in liquid gallium, first with no magnetic field or rotation present, then with the inclusion of a background magnetic field and then in a rotating system (without an imposed magnetic field). In doing so, we demonstrate the essential behaviors of convecting liquid metals that are necessary for understanding and for building accurate, robust models of magnetohydrodynamic processes in $Pm \ll Pr < 1$ geophysical and astrophysical systems.  \\

Back to: Earth and Planetary Magnetic Fields and Core Dynamics