Container-scale hydrodynamic and magnetohydrodynamic modes in liquid metal rotating convection experiments with and without an imposed magnetic field

Abstract:

Thermal convection, constrained by rapid rotation and/or large-scale magnetic fields, is observed almost everywhere in the universe: stars, galaxies, and planetary interiors. However, little is known about the essential behaviors of turbulent convection in liquid metals and even less is known about the essential dynamics of planetary cores and stellar convection zones inuenced by background rotation and imposed magnetic fields. To address this decit, we present novel results of a mixed laboratory-numerical investigation of Rayleigh-Benard convection in a cylindrical cavity subject to rotation and/or an imposed magnetic field, using the liquid metal gallium as the working fluid. A broad variety of cell-sized modes are observed experimentally and captured numerically and these modes can be either? steady, oscillatory, or precessing. This work shows that the convection-driven cell-sized modes that can develop in liquid metals are remarkably different from the canonical flows that develop in the fluids used in present day dynamo models.