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We self-consistently derive the magnetic energy and relative magnetic helicity budgets of a three-dimensional linear force-free magnetic structure rooted in a lower boundary plane. For the potential magnetic energy we derive a general…

Astrophysics · Physics 2009-11-13 M. K. Georgoulis , Barry J. LaBonte

Seven different models are applied to the same problem of simulating the Sun's coronal magnetic field during the solar eclipse on 2015 March 20. All of the models are non-potential, allowing for free magnetic energy, but the associated…

Investigating the solar magnetic field is crucial to understand the physical processes in the solar interior as well as their effects on the interplanetary environment. We introduce a novel method to predict the evolution of the solar…

High-resolution observations show the fine structure of the global equilibrium magnetic field configuration in solar atmosphere to be essentially different from that assumed in the traditional 'potential + force-free' field scenarios. The…

Solar and Stellar Astrophysics · Physics 2012-05-01 L. A. Pustil'nik , N. R. Ikhsanov , N. G. Beskrovnaya

We present evidence for finite magnetic helicity density in the heliosphere and numerical models thereof, and relate it to the magnetic field properties of the dynamo in the solar convection zone. We use simulations and solar wind data to…

Solar and Stellar Astrophysics · Physics 2012-08-03 Jörn Warnecke , Axel Brandenburg , Dhrubaditya Mitra

A statistical analysis of magnetic energies of the nonlinear force-free and potential fields, and their difference (a proxy for the free magnetic energy) in active regions (ARs) on the Sun of different Hale (Mount Wilson) and McIntosh…

Solar and Stellar Astrophysics · Physics 2025-04-15 I. V. Zimovets , I. N. Sharykin , W. -Q. Gan

Using even-order frequency splitting coefficients of global p-modes it is possible to infer the magnetic field in the solar interior as a function of radial distance and latitude. Results obtained using GONG and MDI data are discussed.…

Astrophysics · Physics 2007-05-23 H. M. Antia

A more accurate analytical solution of the {\sl vertical-current approximation nonlinear force-free field (VCA3-NLFFF)} model is presented that includes besides the radial $(B_r)$ and the azimuthal $(B_\varphi)$ magnetic field components a…

Solar and Stellar Astrophysics · Physics 2020-01-08 Markus J. Aschwanden

The data from solar neutrino experiments together with standard solar model predictions are used in order to derive the possible profile of the magnetic field inside the Sun, assuming the existence of a sizeable neutrino magnetic moment and…

Astrophysics · Physics 2009-10-30 Joao Pulido

Helicity measures complexity in the field. Magnetic helicity is given by a volume integral over the scalar product of magnetic field {\bf B} and its vector potential {\bf A}. A direct computation of magnetic helicity in the solar atmosphere…

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

The formation and evolution of active regions is an inherently complex phenomenon. Magnetic fields generated at the base of the convection zone follow a chaotic evolution before reaching the solar surface. In this article, we use a 2-D…

Astrophysics · Physics 2009-11-07 L. Vlahos , T. Fragos , H. Isliker , M. Georgoulis

Identifying universal, topology-independent thresholds in the coronal magnetic fields at onset of solar eruptions is crucial for physics-based prediction of eruptions. To this end, we systematically analyze the evolution of magnetic energy…

Solar and Stellar Astrophysics · Physics 2026-05-13 Xinkai Bian , Chaowei Jiang , Qingjun Liu , Yang Wang , Peng Zou , Xueshang Feng , Pingbing Zuo , Yi Wang

The electromagnetic energy $U_{em}$ stored in the magnetic field of an ideal solenoid at rest appears for a moving observer as $U'_{em} $, a sum of magnetic and electric energies satisfying: $U'_{em} > \gamma U_{em}$. We explain this…

Classical Physics · Physics 2010-06-21 Nelson R. F. Braga , Ranieri V. Nery

The MHD virial theorem may be used to estimate the magnetic energy of active regions based on vector magnetic fields measured at the photosphere or chromosphere. However, the virial estimate depends on the measured vector magnetic field…

Astrophysics · Physics 2009-11-13 M. S. Wheatland , T. R. Metcalf

Context: Relaxation theory offers a straightforward method for estimating the energy that is released when a magnetic field becomes unstable, as a result of continual convective driving. Aims: We present new results obtained from nonlinear…

Solar and Stellar Astrophysics · Physics 2015-06-12 Michael Bareford , Alan Hood , Philippa Browning

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

In this dataset we provide a comprehensive collection of magnetograms (images quantifying the strength of the magnetic field) from the National Aeronautics and Space Administration's (NASA's) Solar Dynamics Observatory (SDO). The dataset…

Solar and Stellar Astrophysics · Physics 2024-02-13 Laura E. Boucheron , Ty Vincent , Jeremy A. Grajeda , Ellery Wuest

Multiscale topological complexity of solar magnetic field is among the primary factors controlling energy release in the corona, including associated processes in the photospheric and chromospheric boundaries. We present a new approach for…

Solar and Stellar Astrophysics · Physics 2015-06-03 Vadim M. Uritsky , Joseph M. Davila

A formula for the magnetostatic energy of a finite magnet is proven. In contrast to common approaches, the new energy identity does not rely on evaluation of a nonlocal boundary integral inside the magnet or the solution of an equivalent…

Computational Physics · Physics 2018-08-02 Lukas Exl

We demonstrate that conservation of global helicity plays only a minor role in determining the nature and consequences of magnetic reconnection in the solar atmosphere. First, we show that observations of the solar coronal magnetic field…

Astrophysics · Physics 2015-06-24 Spiro K. Antiochos , C. Richard DeVore