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Related papers: Modeling coronal magnetic field using spherical ge…

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We use SDO/HMI and SOLIS/VSM photospheric magnetic field measurements to model the force-free coronal field above a solar active region, assuming magnetic forces to dominate. We take measurement uncertainties caused by, e.g., noise and the…

Solar and Stellar Astrophysics · Physics 2015-06-05 J. K. Thalmann , A. Pietarila , X. Sun , T. Wiegelmann

Reliable measurements of the solar magnetic field are still restricted to the photosphere, and our present knowledge of the three-dimensional coronal magnetic field is largely based on extrapolation from photospheric magnetogram using…

Solar and Stellar Astrophysics · Physics 2015-06-05 Chaowei Jiang , Xueshang Feng , Changqing Xiang

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

With the development of new instrumentation providing measurements of solar photospheric vector magnetic fields, we need to develop our understanding of the effects of current density on coronal magnetic field configurations. The object is…

Astrophysics · Physics 2009-11-13 S. Regnier , E. R. Priest

The solar coronal magnetic field produces solar activity, including extremely energetic solar flares and coronal mass ejections (CMEs). Knowledge of the structure and evolution of the magnetic field of the solar corona is important for…

Solar and Stellar Astrophysics · Physics 2015-06-22 Tilaye Tadesse , Thomas Wiegelmann , Peter MacNeice

It is widely believed that loops observed in the solar atmosphere trace out magnetic field lines. However, the degree to which magnetic field extrapolations yield field lines that actually do follow loops has yet to be studied…

Solar and Stellar Astrophysics · Physics 2018-06-27 Harry P. Warren , Nicholas A. Crump , Ignacio Ugarte-Urra , Xudong Sun , Markus J. Aschwanden , Thomas Wiegelmann

In the quiet solar photosphere, the mixed polarity fields form a magnetic carpet, which continuously evolves due to dynamical interaction between the convective motions and magnetic field. This interplay is a viable source to heat the solar…

Solar and Stellar Astrophysics · Physics 2014-09-16 L. P. Chitta , R. Kariyappa , A. A. van Ballegooijen , E. E. DeLuca , S. K. Solanki

In this review, I focus on the structure and evolution of the coronal magnetic fields modelled from observations. The development of instruments measuring the photospheric and chromospheric magnetic fields with a high spatial and time…

Solar and Stellar Astrophysics · Physics 2011-01-18 Stephane Regnier

We developed a {\sl coronal non-linear force-free field (COR-NLFFF)} forward-fitting code that fits an approximate {\sl non-linear force-free field (NLFFF)} solution to the observed geometry of automatically traced coronal loops. In…

Solar and Stellar Astrophysics · Physics 2015-06-18 Markus J. Aschwanden , Xudong Sun , Yang Liu

We describe a newly developed code for the extrapolation of nonlinear force-free coronal magnetic fields in spherical coordinates. The program uses measured vector magnetograms on the solar photosphere as input and solves the force-free…

Astrophysics · Physics 2008-11-26 Thomas Wiegelmann

A combination of analytical calculations and vectormagnetogram data are utilized to develop a non-axisymmetric non-force-free magnetic field and asses its viability in describing solar active regions. For the purpose, we construct a local…

Solar and Stellar Astrophysics · Physics 2016-11-21 A. Prasad , R. Bhattacharyya

The coronal magnetic field plays a fundamental role in governing coronal activities, driving space-weather events, and shaping the heliosphere. Due to a lack of direct observations, extrapolation models such as the Potential Field Source…

Solar and Stellar Astrophysics · Physics 2026-04-02 Ziqi Wu , Jiansen He , Chuanpeng Hou , Tom van Doorsselaere , Rui Zhuo , Tianhang Chen , Liping Yang , David Pontin , Daniel Verscharen , Fang Shen

The nonlinear force-free field (NLFFF) model is often used to describe the solar coronal magnetic field, however a series of earlier studies revealed difficulties in the numerical solution of the model in application to photospheric…

The coronal magnetic field directly or indirectly affects a majority of the phenomena studied in space physics. It provides energy for coronal heating, controls the release of coronal mass ejections (CMEs), and drives heliospheric and…

Solar and Stellar Astrophysics · Physics 2016-04-13 Shaela I. Jones , Joseph M. Davila , Vadim M. Uritsky

The magnetic field in the Sun's corona stores energy that can be released to heat the coronal plasma and drive solar eruptions. Measurements of the global coronal magnetic field have been limited to a few snapshots. We present observations…

Solar and Stellar Astrophysics · Physics 2024-10-23 Zihao Yang , Hui Tian , Steven Tomczyk , Xianyu Liu , Sarah Gibson , Richard J. Morton , Cooper Downs

Coronal heating through the explosive release of magnetic energy remains an open problem in solar physics. Recent hydrodynamical models attempt an investigation by placing swarms of 'nanoflares' at random sites and times in modeled…

Solar and Stellar Astrophysics · Physics 2016-11-30 K. Moraitis , A. Toutountzi , H. Isliker , M. Georgoulis , L. Vlahos , G. Chintzoglou

Knowledge of the structure of the coronal magnetic field is important for our understanding of many solar activity phenomena, e.g. flares and CMEs. However, the direct measurement of coronal magnetic fields is not possible with present…

Astrophysics · Physics 2020-01-29 T. Wiegelmann , T. Neukirch

Recent advances have made it possible to obtain two-dimensional line-of-sight magnetic field maps of the solar corona from spectropolarimetric observations of the Fe XIII 1075 nm forbidden coronal emission line. Together with the linear…

Astrophysics · Physics 2009-11-13 Yu Liu , Haosheng Lin

In this paper a new technique for modeling non-linear force-free fields directly from line of sight magnetogram observations is presented. The technique uses sequences of magnetograms directly as lower boundary conditions to drive the…

Solar and Stellar Astrophysics · Physics 2011-02-28 Duncan H. Mackay , L. M. Green , Aad van Ballegooijen

Extrapolation codes for modelling the magnetic field in the corona in cartesian geometry do not take the curvature of the Sun's surface into account and can only be applied to relatively small areas, \textit{e.g.}, a single active region.…

Solar and Stellar Astrophysics · Physics 2011-04-13 T. Tadesse , T. Wiegelmann , B. Inhester , A. Pevtsov