2009/11/20 by Vincent Morin, Vincent M. Morin, Emmanuel Dormy · 108 citations
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · Physics and Astronomy · #Bifurcation #Classical mechanics #Convection #Dynamo #Dynamo theory #Ekman number #Geomagnetism and Paleomagnetism Studies #Geophysics and Gravity Measurements #Magnetic Prandtl number #Magnetic and Electromagnetic Effects #Magnetic field #Materials science #Mechanics #Nonlinear system #Nusselt number #Physics #Prandtl number #Quantum mechanics #Reynolds number #Shell (structure) #Spherical shell #Supercritical fluid #Thermodynamics #astro-ph.EP #physics.flu-dyn #physics.geo-ph
paper · pdf · doi:10.1142/s021797920906378x
published in International Journal of Modern Physics B 23(28n29), 5467-5482 (World Scientific) · 16 pages, 14 figures
openalex publication_date 2009/11/20 · arxiv created 2010/06/06 · arxiv updated 2014/11/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate the nature of the dynamo bifurcation in a configuration applicable to the Earth's liquid outer core, i.e. in a rotating spherical shell with thermally driven motions. We show that the nature of the bifurcation, which can be either supercritical or subcritical or even take the form of isola (or detached lobes) strongly depends on the parameters. This dependence is described in a range of parameters numerically accessible (which unfortunately remains remote from geophysical application), and we show how the magnetic Prandtl number and the Ekman number control these transitions.