Influence of boundary conditions on rapidly rotating convection and its dynamo action in a plane fluid layer

Abstract

We investigate the influence of thermal, mechanical, and magnetic boundary conditions (BCs) on convective dynamos in a rapidly rotating plane fluid layer using direct numerical simulations. While the velocity BCs largely control whether large-scale flows and fields are generated, the magnetic BCs affect the magnetic field topology. The role of the thermal BCs is of note: For no-slip boundaries, the Nusselt number increases significantly when a fixed heat flux is imposed instead of a given temperature difference. We explain this effect, which applies to both dynamos and nonmagnetic, rotating convection, by an interplay of Ekman pumping and the internal structure of the thermal boundary layer.