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We present results from simulations of rotating magnetized turbulent convection in spherical wedge geometry representing parts of the latitudinal and longitudinal extents of a star. Here we consider a set of runs for which the density…

Solar and Stellar Astrophysics · Physics 2013-11-19 Petri J. Käpylä , Maarit. J. Mantere , Elizabeth Cole , Jörn Warnecke , Axel Brandenburg

Magnetic fields can be created in stably stratified (non-convective) layers in a differentially rotating star. A magnetic instability in the toroidal field (wound up by differential rotation) replaces the role of convection in closing the…

Astrophysics · Physics 2009-11-07 H. C. Spruit

Mixing at the interface between a convection zone and an adjacent, stably-stratified layer plays a crucial role in shaping the structure and evolution of stars and planets. In this work, we present a suite of 2D and 3D Boussinesq…

Fluid Dynamics · Physics 2025-11-06 Bradley W. Hindman , J. R. Fuentes

Divergence and vorticity damping, which operate upon horizontal divergence and relative vorticity, are explicit diffusion mechanisms used in dynamical cores to ensure stability. To avoid numerical blow-up from excessively strong diffusion,…

Numerical Analysis · Mathematics 2026-02-19 Timothy C. Andrews , Christiane Jablonowski

In the stably stratified ocean, small-scale turbulence is important for vertical exchange and hence for the mixing of water masses and suspended matter. To observationally study turbulent motions and the buoyancy- and shear-generators…

Atmospheric and Oceanic Physics · Physics 2022-09-23 Hans van Haren

We analyse a sunspot simulation in an effort to understand the origin of the convective instabilities giving rise to the penumbral and umbral distinct regimes. We applied the criterion from Gough \& Tayler (1966), accounting for the…

Solar and Stellar Astrophysics · Physics 2022-11-01 M. Schmassmann , M. Rempel , N. Bello González , R. Schlichenmaier , J. Jurčák

Stably stratified layers are thought to develop at the top of the liquid metallic cores of many terrestrial planets. We consider the case where the thermal gradient is stable but the compositional gradient is unstable, a situation…

Fluid Dynamics · Physics 2025-11-17 Martin Gray , Celine Guervilly , Graeme Sarson

We perform a linear magnetohydrodynamic perturbation analysis for a stratified magnetized envelope where the diffusion of heat is mediated by charged particles that are confined to flow along magnetic field lines. We identify an…

Astrophysics · Physics 2009-11-13 Aristotle Socrates , Ian J. Parrish , James M. Stone

In this work, we investigate the impact of uncertainties due to convective boundary mixing (CBM), commonly called `overshoot', namely the boundary location and the amount of mixing at the convective boundary, on stellar structure and…

Solar and Stellar Astrophysics · Physics 2020-07-20 Etienne A. Kaiser , Raphael Hirschi , W. David Arnett , Cyril Georgy , Laura J. A. Scott , Andrea Cristini

A monomodal model for stellar and planetary convection is derived for the magnitude of the rms velocity, degree of superadiabaticity, and characteristic length scale as a function of rotation rate as well as with thermal and viscous…

Solar and Stellar Astrophysics · Physics 2019-04-03 Kyle C. Augustson , Stéphane Mathis

Recent research has shed light on the role of coherent structures in forming layers when stably stratified turbulence is forced with horizontal shear (Lucas, Caulfield & Kerswell, J. Fluid Mech., vol. 832, 2017, pp. 409-437). Here we extend…

Fluid Dynamics · Physics 2019-05-01 Dan Lucas , C. P. Caulfield , Rich R. Kerswell

Dynamical stability of the shock compressed layer with finite thickness is investigated. It is characterized by self-gravity, structure, and shock condition at the surfaces of the compressed layer. At one side of the shocked layer, its…

Astrophysics · Physics 2009-10-31 Ryoichi Nishi , Hideyuki Kamaya

Evolution of large-scale scalar perturbations in the presence of stiff solid (solid with pressure to energy density ratio > 1/3) is studied. If the solid dominated the dynamics of the universe long enough, the perturbations could end up…

General Relativity and Quantum Cosmology · Physics 2015-01-29 Vladimír Balek , Matej Škovran

A hypothesis for sunspot formation is the buoyant emergence of magnetic flux tubes created by the strong radial shear at the tachocline. In this scenario, the magnetic field has to exceed a threshold value before it becomes buoyant and…

Solar and Stellar Astrophysics · Physics 2011-10-25 G. Guerrero , P. Käpylä

We study how stably stratified or semi-convective layers alter the tidal dissipation rates associated with the generation of internal waves in planetary interiors. We consider if these layers could contribute to the high rates of tidal…

Earth and Planetary Astrophysics · Physics 2023-07-05 Christina M. Pontin , Adrian J. Barker , Rainer Hollerbach

Recent analyses of the helioseismic data have produced evidence for a variety of interesting dynamical behaviour associated with torsional oscillations. What is not so far clear is whether these oscillations extend all the way to the bottom…

Astrophysics · Physics 2009-11-07 Reza Tavakol , Eurico Covas , David Moss , Andrew Tworkowski

Magnetic fields vary in complexity for different stars. The stability of dipolar magnetic fields is known to depend on different quantities, e.g., the stellar rotation, the stratification, and the intensity of convective motions. Here, we…

Solar and Stellar Astrophysics · Physics 2020-09-30 Bonnie Zaire , Laurene Jouve

Static equilibrium configurations of continua supported by surface tension are given by constant mean curvature (CMC) surfaces which are critical points of a variational problem to extremize the area while keeping the volume fixed. CMC…

Mathematical Physics · Physics 2023-12-05 Miyuki Koiso , Umpei Miyamoto

Stars of sufficiently low mass are convective throughout their interiors, and so do not possess an internal boundary layer akin to the solar tachocline. Because that interface figures so prominently in many theories of the solar magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-20 Matthew Browning

Our ability to predict the structure and evolution of stars is in part limited by complex, 3D hydrodynamic processes such as convective boundary mixing. Hydrodynamic simulations help us understand the dynamics of stellar convection and…

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