Heidelberg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
EP: Fachverband Extraterrestrische Physik
EP 3: Planets and Small bodies
EP 3.4: Vortrag
Dienstag, 22. März 2022, 12:00–12:15, EP-H1
Dynamo models reproducing the offset dipole of Mercury's magnetic field — •Patrick Kolhey1, Daniel Heyner1, Johannes Wicht2, Thomas Gastine3, and Ferdinand Plaschke1 — 1Institut für Geophysik und extraterrestrische Physik, Technische Universität Braunschweig, Braunschweig, Germany — 2Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany — 3Institut de Physique du Globe de Paris, Université de Paris, Paris, France
Since the discovery of Mercury's peculiar magnetic field it has raised questions about the dynamo process in its fluid core. The global magnetic field at the surface is rather weak compared to other planetary magnetic fields, strongly aligned to the planet's rotation axis and its magnetic equator is shifted towards north. Especially the latter characteristic is difficult to explain using common dynamo model setups. In this study we present new direct numerical simulations of the magnetohydrodynamical dynamo problem which include a stably stratified layer on top of the outer core, which can also reproduce the shift of the magnetic equator towards north. We revisit a model configuration for Mercury's dynamo action, which successfully reproduced the magnetic field features, in which core convection is driven by thermal buoyancy as well as compositional buoyancy (double-diffusive convection). While we find that this model configuration produces Mercury-like magnetic field only in a limited parameter range (Rayleigh and Ekman number), we show that also a simple codensity model is sufficient over a wide parameter range to produce Mercury-like magnetic fields.