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We combine a convectively driven dynamo in a spherical shell with a nearly isothermal density-stratified cooling layer that mimics some aspects of a stellar corona to study the emergence and ejections of magnetic field structures. This…

Solar and Stellar Astrophysics · Physics 2012-10-16 Jörn Warnecke , Petri J. Käpylä , Maarit. J. Mantere , Axel Brandenburg

Our aim is to model the 3D magnetic field structure of the upper solar atmosphere, including regions of non-negligible plasma beta. We use high-resolution photospheric magnetic field measurements from SUNRISE/IMaX as boundary condition for…

Solar and Stellar Astrophysics · Physics 2015-12-09 T. Wiegelmann , T. Neukirch , D. H. Nickeler , S. K. Solanki , V. Martinez Pillet , J. M. Borrero

The aim of this study is to explore the suitability of chromospheric images for magnetic modeling of active regions. We use high-resolution images (0.1") from the Interferometric Bidimensional Spectrometer (IBIS) in the Ca II 8542 A line,…

Solar and Stellar Astrophysics · Physics 2016-07-25 M. J. Aschwanden , K. Reardon , D. Jess

When magnetic field in the solar convection zone buoyantly rises to pierce the visible solar surface (photosphere), the atmosphere (corona) above this surface must respond in some way. One response of the coronal field to photospheric…

Solar and Stellar Astrophysics · Physics 2013-09-19 Lucas A. Tarr

Solar magnetic fields play a key role in understanding the nature of the coronal phenomena. Global coronal magnetic fields are usually extrapolated from photospheric fields, for which farside data is taken when it was at the frontside,…

Solar and Stellar Astrophysics · Physics 2022-04-28 Hyun-Jin Jeong , Yong-Jae Moon , Eunsu Park , Harim Lee

Arch-like loop structures filled with million Kelvin hot plasma form the building blocks of the quiet-Sun corona. Both high-resolution observations and magnetoconvection simulations show the ubiquitous presence of magnetic fields on the…

The observed solar activity is believed to be driven by the dissipation of nonpotential magnetic energy injected into the corona by dynamic processes in the photosphere. The enormous range of scales involved in the interaction makes it…

Solar and Stellar Astrophysics · Physics 2015-06-12 Vadim M. Uritsky , Joseph M. Davila , Leon Ofman , Aaron J. Coyner

Regular remote sensing of the magnetic field embedded within the million-degree solar corona is severely lacking. This reality impedes fundamental investigations of the nature of coronal heating, the generation of solar and stellar winds,…

In this work, we introduce a novel generative denoising diffusion model for synthesizing the Sun's three-dimensional coronal magnetic field, a complex and dynamic region characterized by evolving magnetic structures. Despite daily…

Solar and Stellar Astrophysics · Physics 2025-10-03 Daniel E. da Silva , Michael Kirk , Nat Mathews , Andrés Muñoz-Jaramillo

We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated…

Solar and Stellar Astrophysics · Physics 2015-06-15 G. J. D. Petrie

The plasma thermodynamics in the solar upper atmosphere, particularly in the corona, are dominated by the magnetic field, which controls the flow and dissipation of energy. The relative lack of knowledge of the coronal vector magnetic field…

Solar and Stellar Astrophysics · Physics 2016-06-29 N. E. Raouafi , P. Riley , S. Gibson , S. Fineschi , S. K. Solanki

Aims. We show how the build-up of magnetic gradients in the Sun's corona may be inferred directly from photospheric velocity data. This enables computation of magnetic connectivity measures such as the squashing factor without recourse to…

Solar and Stellar Astrophysics · Physics 2015-05-30 A. R. Yeates , G. Hornig , B. T. Welsch

We investigate the dynamics of a closed corona cartesian reduced magnetohydrodynamic (MHD) model where photospheric vortices twist the coronal magnetic field lines. We consider two corotating or counter-rotating vortices localized at the…

Solar and Stellar Astrophysics · Physics 2019-10-17 A. F. Rappazzo , M. Velli , R. B. Dahlburg , G. Einaudi

Optical observations of solar corona provide key information on its magnetic geometry. The large-scale open field of the corona plays an important role in shaping the ambient solar wind and constraining the propagation dynamics of the…

Solar and Stellar Astrophysics · Physics 2025-06-19 Vadim M. Uritsky , Christopher E. Rura , Cooper Downs , Shaela I. Jones , Charles Nickolos Arge , Nathalia Alzate

At the Sun, the strongest magnetic fields are routinely detected at dark sunspots. The magnitude of the field is typically about 3000 G, with only a few exceptions that reported the magnetic field in excess of 5000 G. Given that the…

Solar and Stellar Astrophysics · Physics 2019-08-07 Sergey A. Anfinogentov , Alexey G. Stupishin , Ivan I. Mysh'yakov , Gregory D. Fleishman

Observations of surface magnetic fields are now within reach for many stellar types thanks to the development of Zeeman-Doppler Imaging. These observations are extremely useful for constraining rotational evolution models of stars, as well…

Solar and Stellar Astrophysics · Physics 2015-09-24 Victor Réville , Allan Sacha Brun , Antoine Strugarek , Sean P. Matt , Jérôme Bouvier , Colin P. Folsom , Pascal Petit

A major goal in solar physics has during the last five decades been to find how energy flux generated in the solar convection zone is transported and dissipated in the outer solar layers. Progress in this field has been slow and…

Astrophysics · Physics 2007-05-23 Viggo H. Hansteen , Mats Carlsson , Boris Gudiksen

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs)…

Solar and Stellar Astrophysics · Physics 2017-05-09 A. Prasad , R. Bhattacharyya , Sanjay Kumar

[..] The change in the magnetic configuration due to the increase/decrease of electric current for different force-free models (potential, linear and nonlinear force-free fields) has never been studied in detail before. Here we focus…

Solar and Stellar Astrophysics · Physics 2015-05-28 S. Regnier

The Sun is replete with magnetic fields, with sunspots, pores and plage regions being their most prominent representatives on the solar surface. But even far away from these active regions, magnetic fields are ubiquitous. To a large extent,…

Solar and Stellar Astrophysics · Physics 2015-11-05 Andreas Lagg , Bruce Lites , Jack Harvey , Sanjay Gosain , Rebecca Centeno