2015/02/12 by H. Hotta, M. Rempel, T. Yokoyama · 62 citations
Biochemistry, Genetics and Molecular Biology · Engineering · Physics and Astronomy · #Convection #Convection zone #Dynamo #Field strength #Fluid dynamics and aerodynamics studies #Geomagnetism and Paleomagnetism Studies #Magnetic diffusivity #Magnetohydrodynamics #Mercury's magnetic field #Radiation zone #Solar and Space Plasma Dynamics #Solar dynamo #Thermomagnetic convection #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/803/1/42
published in The Astrophysical Journal 803(1), 42 (IOP Publishing) · 46 pages, 25 figures, 1 table, accepted by ApJ
arxiv created 2015/02/12 · openalex publication_date 2015/04/13 · arxiv updated 2015/06/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We investigate small-scale dynamo action in the solar convection zone through a series of high-resolution MHD simulations in a local Cartesian domain with (solar radius) of horizontal extent and a radial extent from 0.715 to . The dependence of the solution on resolution and diffusivity is studied. For a grid spacing of less than 350 km, the rms magnetic field strength near the base of the convection zone reaches 95% of the equipartition field strength (i.e., magnetic and kinetic energy are comparable). For these solutions the Lorentz force feedback on the convection velocity is found to be significant. The velocity near the base of the convection zone is reduced to 50% of the hydrodynamic one. In spite of the significant decrease of the convection velocity, the reduction in the enthalpy flux is relatively small, since the magnetic field also suppresses the horizontal mixing of the entropy between up- and downflow regions. This effect increases the amplitude of the entropy perturbation and makes convective energy transport more efficient. We discuss potential implications of these results for solar global convection and dynamo simulations.