Russian Journal of Earth Sciences Russian Journal of Earth Sciences Russian Journal of Earth Sciences 1681-1208 46643 10.2205/2018ES000615 ОРИГИНАЛЬНЫЕ СТАТЬИ ORIGINAL ARTICLES ОРИГИНАЛЬНЫЕ СТАТЬИ Latitude dependence of convection and magnetic field generation in the cube Latitude dependence of convection and magnetic field generation in the cube Reshetnyak M Yu Reshetnyak M Yu Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences, Moscow, Russia ru Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences, Moscow, Russia ru 18 1 1 6 29 10 2021 https://rjes.ru/en/nauka/article/46643/view

The 3D thermal convection in the Boussinesq approximation with heating from below and dynamo in the cube are considered. We study dependence of the convection intensity and magnetic field generation on the latitude in $\beta$-plane approximation. It is shown that kinetic energy gradually increases from the poles to the equator more than order of magnitude. The model predicts the strong azimuthal thermal wind, which direction depends on the sign of the thermal convective fluctuations. The spatial scale of the arising flow is comparable to the scale of the physical domain. The magnetic energy increases as well, however dynamo efficiency, i.e., the ratio of the magnetic energy to the kinetic one decreases to the equator. This effect can explain predominance of the dipole configuration of the magnetic field observed in the planets and stars. The approach is useful for modeling of the magnetohydrodynamic turbulence in planetary cores and stellar convective zones.

The 3D thermal convection in the Boussinesq approximation with heating from below and dynamo in the cube are considered. We study dependence of the convection intensity and magnetic field generation on the latitude in $\beta$-plane approximation. It is shown that kinetic energy gradually increases from the poles to the equator more than order of magnitude. The model predicts the strong azimuthal thermal wind, which direction depends on the sign of the thermal convective fluctuations. The spatial scale of the arising flow is comparable to the scale of the physical domain. The magnetic energy increases as well, however dynamo efficiency, i.e., the ratio of the magnetic energy to the kinetic one decreases to the equator. This effect can explain predominance of the dipole configuration of the magnetic field observed in the planets and stars. The approach is useful for modeling of the magnetohydrodynamic turbulence in planetary cores and stellar convective zones.

 Thermal convection magnetic fields planetary and stellar dynamo Thermal convection magnetic fields planetary and stellar dynamo

Arzimovich, L. A., Lukianov, S. Yu. Motion of the charged particles in the electromagnetic fields - M.: Nauka., 1972. - n/a pp. Arzimovich, L. A., Lukianov, S. Yu. Motion of the charged particles in the electromagnetic fields - M.: Nauka., 1972. - n/a pp. Bandaru, V., Boeck, T., Krasnov, D., Schumacher, J. A hybrid finite difference/boundary element procedure for the simulation of turbulent MHD duct flow at finite magnetic Reynolds number, // J. Comp. Phys., 2016. - v. 304 - no. 6 - p. 320. Bandaru, V., Boeck, T., Krasnov, D., Schumacher, J. A hybrid finite difference/boundary element procedure for the simulation of turbulent MHD duct flow at finite magnetic Reynolds number, // J. Comp. Phys., 2016. - v. 304 - no. 6 - p. 320. Brandenburg, A., Subramanian, K. Astrophysical magnetic fields and nonlinear dynamo, // Phys. Rep., 2005. - v. 417 - no. 6 - p. 1. Brandenburg, A., Subramanian, K. Astrophysical magnetic fields and nonlinear dynamo, // Phys. Rep., 2005. - v. 417 - no. 6 - p. 1. Buffett, B. A comparison of subgrid-scale models for large-eddy simulations of convection in the Earth's core, // Geophys. J. Int., 2003. - v. 153 - no. 3 - p. 753. Buffett, B. A comparison of subgrid-scale models for large-eddy simulations of convection in the Earth's core, // Geophys. J. Int., 2003. - v. 153 - no. 3 - p. 753. Busse, F.-H. Thermal instabilities in rapidly rotating systems, // Fluid Mech., 1970. - v. 44 - p. 441. Busse, F.-H. Thermal instabilities in rapidly rotating systems, // Fluid Mech., 1970. - v. 44 - p. 441. Busse, F.H. Convective flows in rapidly rotating spheres and their dynamo action, // Phys. Fluids, 2002. - v. 14 - p. 1301. Busse, F.H. Convective flows in rapidly rotating spheres and their dynamo action, // Phys. Fluids, 2002. - v. 14 - p. 1301. Canuto, C., Hussini, M.~Y., Zang, Q.~A. Spectral Methods in Fluids Dynamics - Berlin: Springer-Verlag., 1988. - 31-75 pp. Canuto, C., Hussini, M.~Y., Zang, Q.~A. Spectral Methods in Fluids Dynamics - Berlin: Springer-Verlag., 1988. - 31-75 pp. Cattaneo, F., et al. On the interaction between convection and magnetic fields, // Astrophys. J., 2003. - v. 588 - no. 2 - p. 1183. Cattaneo, F., et al. On the interaction between convection and magnetic fields, // Astrophys. J., 2003. - v. 588 - no. 2 - p. 1183. Glatzmaier, G., et al. A three-dimensional convective dynamo solution with rotating and finitely conducting inner core and mantle, // Phys. Earth Planet. Int., 1995. - v. 91 - p. 63. Glatzmaier, G., et al. A three-dimensional convective dynamo solution with rotating and finitely conducting inner core and mantle, // Phys. Earth Planet. Int., 1995. - v. 91 - p. 63. Jones, C. A. Convection-driven geodynamo models, // Phil. Trans.~R.~Soc.~London, 2000. - v. A358 - p. 873. Jones, C. A. Convection-driven geodynamo models, // Phil. Trans.~R.~Soc.~London, 2000. - v. A358 - p. 873. Jones, C. A., Roberts, P. H. Convection-driven dynamos in a rotating plane layer, // J. Fluid Mech., 2000. - v. 404 - p. 311. Jones, C. A., Roberts, P. H. Convection-driven dynamos in a rotating plane layer, // J. Fluid Mech., 2000. - v. 404 - p. 311. Pedlosky, J. Geophysical fluid dynamics - Berlin: Springer-Verlag., 2012. - 999 pp. Pedlosky, J. Geophysical fluid dynamics - Berlin: Springer-Verlag., 2012. - 999 pp. Reshetnyak, M., Pavlov, V. Evolution of the Dipole Geomagnetic Field. Observations and Models, // Geomagnetism and Aeronomy, 2016. - v. 56 - no. 1 - p. 110. Reshetnyak, M., Pavlov, V. Evolution of the Dipole Geomagnetic Field. Observations and Models, // Geomagnetism and Aeronomy, 2016. - v. 56 - no. 1 - p. 110. Reshetnyak, M. The anisotropy of hydrodynamical and current helicity, // Astronomy Reports, 2017. - v. 61 - no. 9 - p. 783. Reshetnyak, M. The anisotropy of hydrodynamical and current helicity, // Astronomy Reports, 2017. - v. 61 - no. 9 - p. 783. Roberts, P.-H. On the thermal instability of a rotating-fluid sphere containing heat sources, // Phil.~Trans.~R.~Soc, 1968. - v. A263 - no. 1 - p. 93. Roberts, P.-H. On the thermal instability of a rotating-fluid sphere containing heat sources, // Phil.~Trans.~R.~Soc, 1968. - v. A263 - no. 1 - p. 93. R{ü}diger, G., Hollerbach, R., Kitchatinov, L. L. Magnetic Processes in Astrophysics: Theory, Simulations, Experiments - Weinheim, Germany: Wiley-VCH., 2013. - 356 pp. R{ü}diger, G., Hollerbach, R., Kitchatinov, L. L. Magnetic Processes in Astrophysics: Theory, Simulations, Experiments - Weinheim, Germany: Wiley-VCH., 2013. - 356 pp.