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Modeling the interface region between solar photosphere and corona is challenging, because the relative importance of magnetic and plasma forces change by several orders of magnitude. While the solar corona can be modeled by the force-free…

Solar and Stellar Astrophysics · Physics 2018-10-31 Xiaoshuai Zhu , Thomas Wiegelmann

The structure and dynamics of the solar corona is dominated by the magnetic field. In most areas in the corona magnetic forces are so dominant that all non-magnetic forces like plasma pressure gradient and gravity can be neglected in the…

Solar and Stellar Astrophysics · Physics 2021-03-24 Thomas Wiegelmann , Takashi Sakurai

The coronal magnetic field is an important quantity because the magnetic field dominates the structure of the solar corona. Unfortunately direct measurements of coronal magnetic fields are usually not available. The photospheric magnetic…

Astrophysics · Physics 2009-06-25 T. Wiegelmann

The solar atmosphere being magnetic in nature, the understanding of the structure and evolution of the magnetic field in different regions of the solar atmosphere has been an important task over the past decades. This task has been made…

Solar and Stellar Astrophysics · Physics 2015-06-16 S. Regnier

Understanding structures and evolutions of the magnetic fields and plasma in multiple layers on the Sun is very important. A force-free magnetic field which is an accurate approximation of the solar corona due to the low plasma $\beta$ has…

Solar and Stellar Astrophysics · Physics 2022-03-30 Xiaoshuai Zhu , Thomas Neukirch , Thomas Wiegelmann

Three-dimensional (3D) magnetic field in the solar atmosphere provides crucial information to understand the explosive phenomenon such as solar flares and coronal mass ejections. Since it is still hard that we determine the 3D magnetic…

Solar and Stellar Astrophysics · Physics 2026-01-07 Daiki Yamasaki , Takahiro Miyoshi , Satoshi Inoue

For the extrapolation of magnetic fields into the solar corona from measurements taken in the photosphere (or chromosphere) force-free magnetic fields are typically used. This does not take into account that the lower layers of the solar…

Solar and Stellar Astrophysics · Physics 2020-01-08 Thomas Neukirch , Thomas Wiegelmann

Non-linear force-free extrapolations are a common approach to estimate the 3D topology of coronal magnetic fields based on photospheric vector magnetograms. The force-free assumption is a valid approximation at coronal heights, but for the…

Knowledge regarding the coronal magnetic field is important for the understanding of many phenomena, like flares and coronal mass ejections. Because of the low plasma beta in the solar corona the coronal magnetic field is often assumed to…

Astrophysics · Physics 2008-11-26 Thomas Wiegelmann , Bernd Inhester , Takashi Sakurai

Magnetic neutral points, where the magnitude of the magnetic field vanishes locally, are potential locations for energy conversion in the solar corona. The fact that the magnetic field is identically zero at these points suggests that for…

Solar and Stellar Astrophysics · Physics 2012-02-02 Jorge Fuentes-Fernández , Clare E. Parnell , Alan W. Hood , Eric R. Priest , Dana W. Longcope

Context. For the last thirty years, most of the studies on the relaxation of stressed magnetic fields in the solar environment have onlyconsidered the Lorentz force, neglecting plasma contributions, and therefore, limiting every equilibrium…

Solar and Stellar Astrophysics · Physics 2011-10-25 Jorge Fuentes-Fernández , Clare E. Parnell , Alan W. Hood

The nonlinear force-free field (NLFFF) modeling has been extensively used to infer the three-dimensional (3D) magnetic field in the solar corona. One of the assumptions in the NLFFF extrapolation is that the plasma beta is low, but this…

Solar and Stellar Astrophysics · Physics 2020-07-30 Yusuke Kawabata , Andrés Asensio Ramos , Satoshi Inoue , Toshifumi Shimizu

Routine measurements of the solar magnetic field are mainly carried out in the photosphere. Therefore, one has to infer the field strength in the higher layers of the solar atmosphere from the measured photospheric field based on the…

Solar and Stellar Astrophysics · Physics 2015-05-20 Tilaye Tadesse , T. Wiegelmann , B. Inhester , A. Pevtsov

We compare magnetic field extrapolations from a photospheric magnetogram with the observationally inferred structure of magnetic loops in a newly developed active region. This is the first time that the reconstructed 3D-topology of the…

Astrophysics · Physics 2009-06-25 T. Wiegelmann , A. Lagg , S. K. Solanki , B. Inhester , J. Woch

With current observational methods it is not possible to directly measure the magnetic field in the solar corona with sufficient accuracy. Therefore, coronal magnetic field models have to rely on extrapolation methods using photospheric…

Solar and Stellar Astrophysics · Physics 2025-04-24 Lilli Nadol , Thomas Neukirch

The structure of the solar corona is dominated by the magnetic field because the magnetic pressure is about four orders of magnitude higher than the plasma pressure. Due to the high conductivity the emitting coronal plasma (visible e.g. in…

Astrophysics · Physics 2009-06-25 T. Wiegelmann , B. Inhester , A. Lagg , S. K. Solanki

We present a careful assess of the forced field extrapolation using Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) magnetogram. The convergence property is checked by several metrics. The extrapolated field lines…

Solar and Stellar Astrophysics · Physics 2017-03-22 Xiaoshuai Zhu , Huaning Wang , Zhanle Du , Han He

We present a newly developed approach to solar coronal magnetic field extrapolation from vector magnetograms, based on the Principle of Minimum Dissipation Rate (MDR). The MDR system was derived from a variational problem that is more…

Astrophysics · Physics 2009-11-13 Q. Hu , B. Dasgupta , D. P. Choudhary , J. Büchner

Context: Solar magnetic fields are regularly extrapolated into the corona starting from photospheric magnetic measurements that can suffer from significant uncertainties. Aims: Here we study how inaccuracies introduced into the maps of the…

Solar and Stellar Astrophysics · Physics 2015-05-14 T. Wiegelmann , L. Yelles Chaouche , S. K. Solanki , A. Lagg

This work examines the relation between the fractal properties of the photospheric magnetic patterns and those of the coronal magnetic fields in solar active regions.Our results show no correlation between the fractal dimensions of the…

Solar and Stellar Astrophysics · Physics 2015-05-14 M. Dimitropoulou , M. Georgoulis , H. Isliker , L. Vlahos , A. Anastasiadis , D. Strintzi , X. Moussas
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