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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

In a force-free magnetic field, there is no interaction of field and the plasma in the surrounding atmosphere i.e., electric currents are aligned with the magnetic field, giving rise to zero Lorentz force. The computation of many magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-20 Sanjiv Kumar Tiwari

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

To understand the physics of solar flares, including the local reorganisation of the magnetic field and the acceleration of energetic particles, we have first to estimate the free magnetic energy available for such phenomena, which can be…

Astrophysics · Physics 2008-05-16 S. Regnier , E. R. Priest

Quantifying coronal magnetic field remains a central problem in solar physics. Nowadays the coronal magnetic field is often modelled using nonlinear force-free field (NLFFF) reconstructions, whose accuracy has not yet been comprehensively…

Solar and Stellar Astrophysics · Physics 2018-09-14 Gregory D. Fleishman , Sergey Anfinogentov , Maria Loukitcheva , Ivan Mysh'yakov , Alexey Stupishin

Determining the electric field (E-field) distribution on the Sun's photosphere is essential for quantitative studies of how energy flows from the Sun's photosphere, through the corona, and into the heliosphere. This E-field also provides…

Solar and Stellar Astrophysics · Physics 2014-11-20 G. H. Fisher , B. T. Welsch , W. P. Abbett , D. J. Bercik

The Vector Spectromagnetograph (VSM) of the NSO's Synoptic Optical Long-Term Investigations of the Sun (SOLIS) facility is now operational and obtains the first-ever vector magnetic field measurements of the entire visible solar hemisphere.…

Astrophysics · Physics 2007-07-02 M. K. Georgoulis , N. -E. Raouafi , C. J Henney

This paper is concerned with the Laplace boundary-value problem with the directional derivative, corresponding to the specific nature of measurements of the longitudinal component of the photospheric magnetic field. Boundary conditions are…

Astrophysics · Physics 2015-06-24 G. V. Rudenko

In order to understand the influence of magnetic fields on the propagation properties of waves, as derived from different local helioseismology techniques, forward modeling of waves is required. Such calculations need a model in…

Astrophysics · Physics 2009-11-13 E. Khomenko , M. Collados

A magneto-hydrostatic model is constructed with spectropolarimetric properties close to those of solar photospheric magnetic bright points. Results of solar radiative magneto-convection simulations are used to produce the spatial structure…

Solar and Stellar Astrophysics · Physics 2015-05-18 S. Shelyag , M. Mathioudakis , F. P. Keenan , D. B. Jess

Although it is generally believed that the solar photosphere is not magnetically force-free owning to its high plasma $\beta$, the estimations of force-freeness using observed magnetograms have produced disputable results. Some studies…

Solar and Stellar Astrophysics · Physics 2023-09-28 Mei Zhang , Haocheng Zhang

We present a new computational method for smoothly matching general relativistic ideal magnetohydrodynamics (MHD) to its force-free limit. The method is based on a flux-conservative formalism for MHD and its force-free limit, and a vector…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Vasileios Paschalidis , Stuart L. Shapiro

Force-freeness of a solar magnetic field is a key to reconstructing invisible coronal magnetic structure of an emerging flux region on the Sun where active phenomena such as flares and coronal mass ejections frequently occur. We have…

Solar and Stellar Astrophysics · Physics 2015-06-23 Jihye Kang , Tetsuya Magara

We develop a general description of how information propagates through a magnetohydrodynamic (MHD) system based on the method of characteristics and use that to formulate numerical boundary conditions (BCs) that are intrinsically consistent…

Solar and Stellar Astrophysics · Physics 2023-11-07 Lucas A. Tarr , N. Dylan Kee , Mark G. Linton , Peter W. Schuck , James E. Leake

We present a novel numerical method that allows the calculation of nonlinear force-free magnetostatic solutions above a boundary surface on which only the distribution of the normal magnetic field component is given. The method relies on…

Solar and Stellar Astrophysics · Physics 2015-05-20 Ioannis Contopoulos , Constantinos Kalapotharakos , Manolis Georgoulis

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

We use daily full-disk vector magnetograms from Vector Spectromagnetograph (VSM) on Synoptic Optical Long-term Investigations of the Sun (SOLIS) system to synthesize the first Carrington maps of the photospheric vector magnetic field. We…

Solar and Stellar Astrophysics · Physics 2015-06-15 S. Gosain , A. A. Pevtsov , G. V. Rudenko , S. A. Anfinogentov

A magnetic field is force-free if there is no interaction between the magnetic field and plasma in surrounding atmosphere i.e., electric currents are aligned with the magnetic field, giving rise to zero Lorentz force. Computation of various…

Solar and Stellar Astrophysics · Physics 2015-05-30 Sanjiv Kumar Tiwari

Within the context of a viscoresistive magnetohydrodynamic (MHD) model with anisotropic heat transport and cross-field mass diffusion, we introduce novel three-term representations for the magnetic field (background vacuum field, field line…

Plasma Physics · Physics 2019-10-15 Nikita Nikulsin , Matthias Hoelzl , Alessandro Zocco , Karl Lackner , Sibylle Günter

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