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We demonstrate that a magneto-convection simulation incorporating essential physical processes governing solar surface convection exhibits turbulent small-scale dynamo action. By presenting a derivation of the energy balance equation and…

Solar and Stellar Astrophysics · Physics 2010-04-23 Jonathan Pietarila Graham , Robert Cameron , Manfred Schuessler

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

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

The aim of this article is to study how the differential rotation of solar-like stars is influenced by rotation rate and mass in presence of magnetic fields generated by a convective dynamo. We use the ASH code to model the convective…

Solar and Stellar Astrophysics · Physics 2016-09-21 J. Varela , A. Strugarek , A. S. Brun

Magnetohydrodynamic star-in-a-box simulations of convection and dynamos in a solar-like star with different rotation rates are presented. These simulations produce solar-like differential rotation with a fast equator and slow poles, and…

Solar and Stellar Astrophysics · Physics 2022-06-08 Petri J. Käpylä

This review provides an introduction to the generation and evolution of the Sun's magnetic field, summarising both observational evidence and theoretical models. The eleven year solar cycle, which is well known from a variety of observed…

Solar and Stellar Astrophysics · Physics 2011-10-17 Alan W. Hood , David W. Hughes

The small-scale magnetic field is ubiquitous at the solar surface---even at high latitudes. From observations we know that this field is uncorrelated (or perhaps even weakly anticorrelated) with the global sunspot cycle. Our aim is to…

Solar and Stellar Astrophysics · Physics 2016-01-11 Bidya Binay Karak , Axel Brandenburg

The operation of the solar dynamo, with all of its remarkable spatio-temporal ordering, remains an outstanding problem of modern solar physics. A number of mechanisms that might plausibly contribute to its operation have been proposed, but…

(abridged) Aims: Three-dimensional numerical simulations of penetrative compressible convection with uniform horizontal shear are used to study dynamo action and the generation of large-scale magnetic fields. Methods: We consider cases…

Astrophysics · Physics 2008-11-10 P. J. Käpylä , M. J. Korpi , A. Brandenburg

This study aims at investigating the ability of strong interactions between magnetic field concentrations during their rise through the convection zone to produce complex active regions at the solar surface. To do so, we perform numerical…

Solar and Stellar Astrophysics · Physics 2018-05-02 L. Jouve , A. S. Brun , G. Aulanier

Global dynamo simulations solving the equations of magnetohydrodynamics (MHD) have been a tool of astrophysicists who try to understand the magnetism of the Sun for several decades now. During recent years many fundamental issues in dynamo…

Solar and Stellar Astrophysics · Physics 2011-07-08 P. J. Käpylä

We recently presented the first 3D numerical simulation of the solar interior for which tachocline confinement was achieved by a dynamo-generated magnetic field. In this followup study, we analyze the degree of confinement as the magnetic…

Solar and Stellar Astrophysics · Physics 2024-01-09 Loren I. Matilsky , Nicholas H. Brummell , Bradley W. Hindman , Juri Toomre

It is well-known that the cores of massive stars sustain a stellar dynamo with a complex magnetic field configuration. However, the same cannot be said for the field's strength and geometry at the convective-radiative boundary, which are…

Solar and Stellar Astrophysics · Physics 2024-12-16 Rathish P. Ratnasingam , Philipp V. F. Edelmann , Dominic M. Bowman , Tamara M. Rogers

Magnetic reconnection, a fundamentally important process in many aspects of astrophysics, is believed to be initiated by the tearing instability of an electric current sheet, a region where magnetic field abruptly changes direction and…

Solar and Stellar Astrophysics · Physics 2020-03-11 James Leake , Lars Daldorff , James Klimchuk

Since the discovery of solar cycle related with magnetic field in 1908, deep seated oscillatory dynamo has been studied extensively. However, there are still open questions on the solar dynamo, e.g., asymmetric conversion between…

Solar and Stellar Astrophysics · Physics 2018-10-16 Biping Gong

The goal of this research is to investigate how magnetic field affects the dynamics of granular convection and excitation of solar oscillations by means of realistic numerical simulations. We have used a 3D, compressible, non-linear…

Astrophysics · Physics 2008-05-27 L. Jacoutot , A. G. Kosovichev , A. Wray , N. N. Mansour

The emergence of active regions on the Sun is an integral feature of the solar dynamo mechanism. However, details about the generation of active-region-scale magnetism and the journey of this magnetic flux to the photosphere are still in…

Solar and Stellar Astrophysics · Physics 2023-06-13 Maria A. Weber , Hannah Schunker , Laurène Jouve , Emre Işık

Magnetic activity is a ubiquitous feature of stars with convective outer layers, with implications from stellar evolution to planetary atmospheres. Investigating the mechanisms responsible for the observed stellar activity signals from days…

Solar and Stellar Astrophysics · Physics 2023-10-17 Emre Işık , Jennifer L. van Saders , Ansgar Reiners , Travis S. Metcalfe

The question of the origin and evolution of magnetic fields in stars possessing a radiative envelope, like the A-type stars, is still regarded as a challenge for stellar physics. Those zones are likely to be differentially rotating, which…

Solar and Stellar Astrophysics · Physics 2015-06-23 Laurène Jouve , Thomas Gastine , François Lignières

The Sun and other cool stars harbouring outer convection zones manifest magnetic activity in their atmospheres. The connection between this activity and the properties of a deep-seated dynamo generating the magnetic flux is not well…

Solar and Stellar Astrophysics · Physics 2015-05-27 Emre Işık , Dieter Schmitt , Manfred Schüssler
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