2010/03/19 by N. Gómez Pérez, Natalia Gomez-Perez, Moritz H. Heimpel +2 · 1 citation
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · Physics and Astronomy · #Conductivity #Dynamo #Electrical resistivity and conductivity #Geology #Geomagnetism and Paleomagnetism Studies #Geophysical and Geoelectrical Methods #Geophysics #Geophysics and Gravity Measurements #Magnetic field #Materials science #Mechanics #Physics #astro-ph.EP #physics.geo-ph
paper · pdf · doi:10.1016/j.pepi.2010.03.006
30 pages, 11 figures, 2 tables. To be published in Physics of Earth and Planetary Interiors (PEPI).
arxiv created 2010/03/19 · arxiv updated 2010/03/23 · openalex publication_date 2010/03/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The transition from liquid metal to silicate rock in the cores of the terrestrial planets is likely to be accompanied by a gradient in the composition of the outer core liquid. The electrical conductivity of a volatile enriched liquid alloy can be substantially lower than a light-element-depleted fluid found close to the inner core boundary. In this paper, we investigate the effect of radially variable electrical conductivity on planetary dynamo action using an electrical conductivity that decreases exponentially as a function of radius. We find that numerical solutions with continuous, radially outward decreasing electrical conductivity profiles result in strongly modified flow and magnetic field dynamics, compared to solutions with homogeneous electrical conductivity. The force balances at the top of the simulated fluid determine the overall character of the flow. The relationship between Coriolis and Lorentz forces near the outer boundary controls the flow and magnetic field intensity and morphology of the system. Our results imply that a low conductivity layer near the top of Mercury's liquid outer core is consistent with its weak magnetic field.