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Turbulence plays a key role for forming the complex geometry of the large-scale current sheet (CS) and fast energy release in a solar eruption. In this paper, we present full 3D high-resolution simulations for the process of a moderate…

Solar and Stellar Astrophysics · Physics 2023-08-21 Jing Ye , John C. Raymond , Zhixing Mei , Qiangwei Cai , Yuhao Chen , Yan Li , Jun Lin

A grid of numerical simulations of double-diffusive convection is presented for the astrophysical case where viscosity (Prandtl number Pr) and solute diffusivity (Lewis number Le) are much smaller than the thermal diffusivity. As in…

Solar and Stellar Astrophysics · Physics 2015-06-15 F. Zaussinger , H. Spruit

Pulsation period evolution during the helium-shell flash in the Mira variable R Hya is investigated using consistent stellar evolution and non-linear stellar pulsation computations. The initial and time-dependent inner boundary conditions…

Solar and Stellar Astrophysics · Physics 2024-02-16 Yuri A. Fadeyev

The advent of helioseismology has determined in detail the average rotation rate of the Sun as a function of radius and latitude. These data immediately reveal two striking boundary layers of shear in the solar convection zone (CZ): a…

Solar and Stellar Astrophysics · Physics 2019-03-06 Loren I. Matilsky , Bradley W. Hindman , Juri Toomre

In a previous work (MGV18), we showed numerically that the turbulent cascade generated by quasi-2D structures (with wave vectors mostly-perpendicular to the mean magnetic field) is able to generate a temperature profile close to the one…

Solar and Stellar Astrophysics · Physics 2020-10-14 Victor Montagud-Camps , Roland Grappin , Andrea Verdini

Large-eddy simulations (LES) and implicit LES (ILES) are wise and affordable alternatives to the unfeasible direct numerical simulations (DNS) of turbulent flows at high Reynolds numbers (Re). However, for systems with few observational…

Solar and Stellar Astrophysics · Physics 2022-04-13 H. D. Nogueira , G. Guerrero , P. K. Smolarkiewicz , A. G. Kosovichev

We investigate the interplay between the ionization radiation from massive stars and the turbulence inside the surrounding molecular gas thanks to 3D numerical simulations. We used the 3D hydrodynamical code HERACLES to model an initial…

Solar and Stellar Astrophysics · Physics 2015-06-05 P. Tremblin , E. Audit , V. Minier , W. Schmidt , N. Schneider

[Abridged] Bipolar magnetic regions are formed when loops of magnetic flux emerge at the solar photosphere. Our aim is to investigate the flux emergence process in a simulation of granular convection. In particular we aim to determine the…

Solar and Stellar Astrophysics · Physics 2012-08-09 Paul J Bushby , Vasilis Archontis

During the recent years significant progress has been made in the modeling of red giant atmospheres with the aid of 3D hydrodynamical model atmosphere codes. In this contribution we provide an overview of selected results obtained in this…

Solar and Stellar Astrophysics · Physics 2013-05-16 A. Kucinskas , H. -G. Ludwig , M. Steffen , V. Dobrovolskas , J. Klevas , D. Prakapavicius , E. Caffau , P. Bonifacio

We analyze spectral properties of solar convection in the range of depths from 0 to 19~Mm using subsurface flow maps obtained by the time-distance heiioseismology analysis of solar-oscillation data from the Helioseismic and Magnetic Imager…

Solar and Stellar Astrophysics · Physics 2022-03-01 Alexander V. Getling , Alexander G. Kosovichev

Very weakly density-stratified, near-homogeneous 'NH' conditions are found in the deep Western Mediterranean Sea. Under these conditions, over vertical ranges of several hundreds of meters water temperature varies only a few 0.0001degrC and…

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

The evolution of the first generations of stars at zero or extremly low metallicity, and especially some crucial properties like the primary N14 production, is charactarized by convective-reactive mixing events that are mostly absent from…

Astrophysics · Physics 2009-06-23 Paul Woodward , Falk Herwig , David Porter , Tyler Fuchs , Anthony Nowatzki , Marco Pignatari

Solar-type stars exhibit a rich variety of magnetic activity. Seeking to explore the convective origins of this activity, we have carried out a series of global 3D magnetohydrodynamic (MHD) simulations with the anelastic spherical harmonic…

Solar and Stellar Astrophysics · Physics 2015-06-12 Nicholas J. Nelson , Benjamin P. Brown , A. Sacha Brun , Mark S. Miesch , Juri Toomre

(abridged) Context. Turbulent fluxes of angular momentum and heat due to rotationally affected convection play a key role in determining differential rotation of stars. Here we perform a systematic comparison between Cartesian and spherical…

Solar and Stellar Astrophysics · Physics 2011-07-07 P. J. Käpylä , M. J. Mantere , G. Guerrero , A. Brandenburg , P. Chatterjee

We perform large-scale numerical simulations of convection in 3D porous media at Rayleigh-Darcy numbers up to $Ra=8\times10^4$. To investigate the convective mixing of carbon dioxide (CO$_2$) in geological formations, we consider a…

Fluid Dynamics · Physics 2025-03-27 Marco De Paoli , Francesco Zonta , Lea Enzenberger , Eliza Coliban , Sergio Pirozzoli

We use a suite of hydrodynamical cosmological simulations from the Evolution and Assembly of GaLaxies and their Environments (EAGLE) project to investigate the formation of hot hydrostatic haloes and their dependence on feedback mechanisms.…

Astrophysics of Galaxies · Physics 2017-11-01 Camila A. Correa , Joop Schaye , J. Stuart B. Wyithe , Alan R. Duffy , Tom Theuns , Robert A. Crain , Richard Bower

Convection and magnetic field generation in the Earth and planetary interiors are driven by both thermal and compositional gradients. In this work numerical simulations of finite-amplitude double-diffusive convection and dynamo action in…

Fluid Dynamics · Physics 2021-01-27 James F. Mather , Radostin D. Simitev

Contemporary three-dimensional physics-based simulations of the solar convection zone disagree with observations. They feature differential rotation substantially different from the true rotation inferred by solar helioseismology and…

Solar and Stellar Astrophysics · Physics 2023-11-23 Parag Gupta , David MacTaggart , Radostin D. Simitev

Turbulent convection processes in nature are often found to be organized in a hierarchy of plume structures and flow patterns. The gradual aggregation of convection cells or granules to a supergranule which eventually fills the whole…

Fluid Dynamics · Physics 2021-03-16 Philipp P. Vieweg , Janet D. Scheel , Jörg Schumacher

Rayleigh-B\'enard convection in rotating spherical shells can be considered as a simplified analogue of many astrophysical and geophysical fluid flows. Here, we use three-dimensional direct numerical simulations to study this physical…

Fluid Dynamics · Physics 2016-11-23 T. Gastine , J. Wicht , J. Aubert