Heat transfer and flow regimes in quasi-static magnetoconvection with a vertical magnetic field

Abstract

Numerical simulations of quasi-static magnetoconvection with a vertical magnetic field are carried out up to a Chandrasekhar number of $Q=10^8$ over a broad range of Rayleigh numbers $Ra$. Three magnetoconvection regimes are identified: two of the regimes are magnetically-constrained in the sense that a leading-order balance exists between the Lorentz and buoyancy forces, whereas the third regime is characterized by unbalanced dynamics that is similar to non-magnetic convection. Each regime is distinguished by flow morphology, momentum and heat equation balances, and heat transport behavior. One of the magnetically-constrained regimes appears to represent an `ultimate' magnetoconvection regime in the dual limit of asymptotically-large buoyancy forcing and magnetic field strength; this regime is characterized by an interconnected network of anisotropic, spatially-localized fluid columns aligned with the direction of the imposed magnetic field that remain quasi-laminar despite having large flow speeds. As for non-magnetic convection, heat transport is controlled primarily by the thermal boundary layer. Empirically, the scaling of the heat transport and flow speeds with $Ra$ appear to be independent of the thermal Prandtl number within the magnetically-constrained, high-$Q$ regimes.

arXiv comment24 pages, 11 figures

References in corpus (14)

• Large scale dynamics in turbulent Rayleigh-Benard convection
• Scaling in thermal convection: A unifying theory
• Approaching the Asymptotic Regime of Rapidly Rotating Convection: Boundary Layers vs Interior Dynamics
• Transport properties for liquid silicon-oxygen-iron mixtures at Earth's core conditions
• Spherical convective dynamos in the rapidly rotating asymptotic regime
• Transition to the ultimate regime in two-dimensional Rayleigh-Bénard convection
• The ultimate state of thermal convection
• Inverse cascade and symmetry breaking in rapidly-rotating Boussinesq convection
• Large-scale vortices in rapidly rotating Rayleigh-Bénard convection
• Radiative heating achieves the ultimate regime of thermal convection
• Approaching a realistic force balance in geodynamo simulations
• Jump Rope Vortex in Liquid Metal Convection
• Wall modes in magnetoconvection at high Hartmann numbers
• Heat and momentum transfer for magnetoconvection in a vertical external magnetic field

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