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We simulate the buoyant rise of a magnetic flux rope from the solar convection zone into the corona to better understand the energetic coupling of the solar interior to the corona. The magnetohydrodynamic model addresses the physics of…

Solar and Stellar Astrophysics · Physics 2015-06-03 Fang Fang , Ward Manchester , William P. Abbett , Bart van der Holst

Solar active regions are driven dissipative dynamical systems. The turbulent convection zone forces new magnetic flux tubes to rise above the photosphere and shuffles the magnetic fields which are already above the photosphere. The driven…

Astrophysics · Physics 2009-09-29 Loukas Vlahos

Fast rotating cool stars are characterised by high magnetic activity levels and frequently show dark spots up to polar latitudes. Their distinctive surface distributions of magnetic flux are investigated in the context of the solar-stellar…

Astrophysics · Physics 2008-11-26 V. Holzwarth

One interpretation of the activity and magnetism of late-type stars is that these both intensify with decreasing Rossby number up to a saturation level, suggesting that stellar dynamos depend on both rotation and convective turbulence. Some…

Solar and Stellar Astrophysics · Physics 2020-03-23 Jyri J. Lehtinen , Federico Spada , Maarit J. Käpylä , Nigul Olspert , Petri J. Käpylä

The tachocline is important in the solar dynamo for the generation and the storage of the magnetic fields. A most plausible explanation for the confinement of the tachocline is given by the fast tachocline model in which the tachocline is…

Solar and Stellar Astrophysics · Physics 2013-10-01 Bidya Binay Karak , Kristof Petrovay

Simulations of magnetohydrodynamics convection in slowly rotating stars predict anti-solar differential rotation (DR) in which the equator rotates slower than poles. This anti-solar DR in the usual $\alpha \Omega$ dynamo model does not…

Solar and Stellar Astrophysics · Physics 2020-01-01 Bidya Binay Karak , Aparna Tomar , Vindya Vashishth

Global and semi-global convective dynamo simulations of solar-like stars are known to show a transition from an anti-solar (fast poles, slow equator) to solar-like (fast equator, slow poles) differential rotation (DR) for increasing…

Solar and Stellar Astrophysics · Physics 2019-11-25 M. Viviani , M. J. Käpylä , J. Warnecke , P. J. Käpylä , M. Rheinhardt

The solar tachocline is an internal region of the Sun possessing strong radial and latitudinal shears straddling the base of the convective envelope. Based on helioseismic inversions, the tachocline is known to be thin (less than 5\% of the…

Solar and Stellar Astrophysics · Physics 2023-11-22 Antoine Strugarek , Bernadett Belucz , Allan Sacha Brun , Mausumi Dikpati , Gustavo Guerrero

Convectively driven dynamos with rotation generating magnetic fields on scales large compared with the scale of the turbulent eddies are being reviewed. It is argued that such fields can be understood as the result of an alpha effect.…

Solar and Stellar Astrophysics · Physics 2011-08-19 A. Brandenburg , P. J. Käpylä , M. J. Korpi

Torsional oscillations represent bands of fast and slow zonal flows around the Sun, which extend deep into the convection zone and migrate during solar cycles towards the equator following the sunspot butterfly diagram. Analysis of…

Solar and Stellar Astrophysics · Physics 2019-01-15 Alexander G. Kosovichev , Valery V. Pipin

The generation of solar non-axisymmetric magnetic fields is studied based on a linear alpha2-Omega dynamo model in a rotating spherical frame. The model consists of a solar-like differential rotation, a magnetic diffusivity varied with…

Astrophysics · Physics 2008-11-26 Jie Jiang , Jingxiu Wang

The magnetic activity of the Sun, as manifested in the sunspot cycle, originates deep within its convection zone through a dynamo mechanism which involves non-trivial interactions between the plasma and magnetic field in the solar interior.…

Solar and Stellar Astrophysics · Physics 2015-05-13 Dibyendu Nandy

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

This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also…

Solar and Stellar Astrophysics · Physics 2015-06-23 Thomas Wiegelmann , Julia K. Thalmann , Sami K. Solanki

Magnetic fields play a crucial role at all stages of the formation of low mass stars and planetary systems. In the final stages, in particular, they control the kinematics of in-falling gas from circumstellar discs, and the launching and…

Solar and Stellar Astrophysics · Physics 2015-05-19 S. G. Gregory , M. Jardine , C. G. Gray , J. -F. Donati

The study of stellar activity is important because it can provide new constraints for dynamo models, when combined with surface rotation rates and the depth of the convection zone. We know that the dynamo mechanism, which is believed to be…

Solar and Stellar Astrophysics · Physics 2015-06-18 S. Mathur , R. A. Garcia , J. Ballot , T. Ceillier , D. Salabert , T. S. Metcalfe , C. Regulo , A. Jimenez , S. Bloemen

Recent analyses of helioseismological observations seem to suggest the presence of two new phenomena connected with the dynamics of the solar convective zone. Firstly, there are present torsional oscillations with periods of about 11 years,…

Astrophysics · Physics 2009-10-31 Eurico Covas , Reza Tavakol , David Moss

Stellar magnetic fields are produced by a magnetohydrodynamic dynamo mechanism working in their interior -- which relies on the interaction between plasma flows and magnetic fields. The Sun, being a well-observed star, offers an unique…

Solar and Stellar Astrophysics · Physics 2015-06-03 Dibyendu Nandy

The leading theoretical paradigm for the Sun's magnetic cycle is an $\alpha\omega$-dynamo process, in which a combination of differential rotation and turbulent, helical flows produces a large-scale magnetic field that reverses every 11…

Solar and Stellar Astrophysics · Physics 2023-01-16 Craig D. Duguid , Paul J. Bushby , Toby S. Wood

We present axisymmetric simulations of the coupled convective and radiative regions in the Sun in order to investigate the angular momentum evolution of the radiative interior. Both hydrodynamic and magnetohydrodynamic models were run. We…

Solar and Stellar Astrophysics · Physics 2015-05-28 T. M. Rogers