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Large regions of giant planets are thought to possess unstable thermal gradients stabilised by gradients in heavy-element composition. The fluid can then develop semi-convection, a double-diffusive instability driven by the unequal…

Fluid Dynamics · Physics 2026-05-27 Paul Pružina , Nathanaël Schaeffer , David Cébron

We present an attempt to reach realistic turbulent regime in direct numerical simulations of the geodynamo. We rely on a sequence of three convection-driven simulations in a rapidly rotating spherical shell. The most extreme case reaches…

To explore the combined effects of partial thermal stable stratification and magnetic back-reaction within Earth's tangent cylinder, we study the onset of magnetoconvection in an infinite plane layer subject to horizontal magnetic field…

Fluid Dynamics · Physics 2026-02-10 Tirtharaj Barman , Arpan Das , Swarandeep Sahoo

This study examines the onset of rotating magnetoconvection under an axially imposed magnetic field in the presence of partial thermal stable stratification. Three stratification models-fully unstable, weakly stable, and strongly stable-are…

Fluid Dynamics · Physics 2025-11-18 Tirtharaj Barman , Swarandeep Sahoo

The geodynamo features a broad separation between the large scale at which Earth's magnetic field is sustained against ohmic dissipation and the small scales of the turbulent and electrically conducting underlying fluid flow in the outer…

Geophysics · Physics 2019-06-26 J. Aubert

There has been significant recent work which examines a situation where a thin magnetic layer is `draped' over a core merging into a larger cluster; the same process also appears to be at work at a bubble rising from the cluster centre.…

Astrophysics · Physics 2009-11-13 L. J. Dursi

The objective of this paper is to investigate whether a convective dynamo can account quantitatively for the observed lower limit of X-ray surface flux in solar-type main sequence stars. Our approach is to use 3D numerical simulations of a…

Astrophysics · Physics 2009-11-11 D. J. Bercik , G. H. FIsher , C. M. Johns-Krull , W. P. Abbett

Magnetic fields are hypothesized to inflate the radii of low-mass stars---defined as less massive than 0.8$M_\odot$---in detached eclipsing binaries (DEBs). We investigate this hypothesis using the recently introduced magnetic Dartmouth…

Solar and Stellar Astrophysics · Physics 2013-12-09 Gregory A. Feiden , Brian Chaboyer

Inner core translation, with solidification on one hemisphere and melting on the other, provides a promising basis for understanding the hemispherical dichotomy of the inner core, as well as the anomalous stable layer observed at the base…

Geophysics · Physics 2015-06-16 Renaud Deguen , Thierry Alboussière , Philippe Cardin

Context: Convectively-driven flows play a crucial role in the dynamo processes that are responsible for producing magnetic activity in stars and planets. It is still not fully understood why many astrophysical magnetic fields have a…

Solar and Stellar Astrophysics · Physics 2018-05-09 P. J. Bushby , P. J. Käpylä , Y. Masada , A. Brandenburg , B. Favier , C. Guervilly , M. J. Käpylä

Convection-driven flows in planetary interiors exhibit rich dynamics owing to multiple spatio-temporally varying forcing conditions and physical constraints. In particular, the churning of liquid metals in the Earth's outer core,…

Fluid Dynamics · Physics 2024-12-09 Tirtharaj Barman , Swarandeep Sahoo

The stable boundary layer (SBL) subjected to large-scale subsidence is studied through large-eddy simulations (LESs) with fixed surface temperature and a linear subsidence velocity profile. These boundary layers reach a truly steady state,…

Fluid Dynamics · Physics 2024-10-18 Thijs Bon , Raúl Bayoán Cal , Johan Meyers

Vertically stable in density, stratified-water conditions 'SW' exist in the deep Mediterranean Sea that are characterized by temperature differences of 0.0002-0.01degrC over 125 m above a flat seafloor. These result in a mean buoyancy…

Atmospheric and Oceanic Physics · Physics 2026-01-09 Hans van Haren

It is believed that some stars have two or more convection zones in close proximity near to the stellar photosphere. These zones are separated by convectively stable regions that are relatively narrow. Due to the close proximity of these…

Astrophysics · Physics 2008-12-18 M. -K. Lin , L. J. Silvers , M. R. E. Proctor

Current structure models of Jupiter and Saturn suggest that helium becomes immiscible in hydrogen in the outer part of the planets' electrically conducting regions. This likely leads to a layer in which overturning convection is inhibited…

Earth and Planetary Astrophysics · Physics 2025-08-07 Paula N. Wulff , Hao Cao , Jonathan M. Aurnou

Context: Observations indicate that the `quiet' solar photosphere outside active regions contains considerable amounts of magnetic energy and magnetic flux, with mixed polarity on small scales. The origin of this flux is unclear. Aims: We…

Astrophysics · Physics 2009-11-13 A. Voegler , M. Schuessler

There is a clear distinction between simple laminar and complex turbulent fluids. But in some cases, as for the nocturnal planetary boundary layer, a stable and well-ordered flow can develop intense and sporadic bursts of turbulent activity…

Fluid Dynamics · Physics 2015-06-17 C. Rorai , P. D. Mininni , A. Pouquet

In addition to its global North-South anisotropy(1), there are two other enigmatic seismological observations related to the Earth's inner core: asymmetry between its eastern and western hemispheres(2-6) and the presence of a layer of…

Geophysics · Physics 2012-01-06 Thierry Alboussiere , Renaud Deguen , Mickael Melzani

In this contribution we present initial results of a study on convective boundary mixing (CBM) in massive stellar models using the GENEVA stellar evolution code. Before undertaking costly 3D hydrodynamic simulations, it is important to…

Solar and Stellar Astrophysics · Physics 2015-06-23 Andrea Cristini , Raphael Hirschi , Cyril Georgy , Casey Meakin , David Arnett , Maxime Viallet

Early-type stars have convective cores due to a steep temperature gradient produced by the CNO cycle. These cores can host dynamos, and the generated magnetic fields can be relevant to explain the magnetism observed in Ap/Bp stars. Our main…

Solar and Stellar Astrophysics · Physics 2024-11-27 J. P. Hidalgo , P. J. Käpylä , D. R. G Schleicher , C. A. Ortiz-Rodríguez , F. H. Navarrete