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The shapes of solar coronal loops are sensitive to the presence of electrical currents that are the carriers of the nonpotential energy available for impulsive activity. We use this information in a new method for modeling the coronal…

Solar and Stellar Astrophysics · Physics 2021-06-29 A. Malanushenko , C. Schrijver , M. L. DeRosa , M. S. Wheatland

Abridged. Fast rotating and self-gravitating astrophysical objects suffer strong deformations from centrifugal forces. If moreover they are magnetized, they generate an electromagnetic wave that is perturbed accordingly. When stellar…

High Energy Astrophysical Phenomena · Physics 2022-03-23 Jérôme Pétri

We demonstrate the sensitivity of magnetic energy and helicity computations regarding the quality of the underlying coronal magnetic field model. We apply the method of Wiegelmann & Inhester (2010) to a series of SDO/HMI vector…

Solar and Stellar Astrophysics · Physics 2019-07-24 Julia K. Thalmann , Luis Linan , Etienne Pariat , Gherardo Valori

Circuit models involving bulk currents and inductances are often used to estimate the energies of coronal magnetic field configurations, in particular configurations associated with solar flares. The accuracy of circuit models is tested by…

Astrophysics · Physics 2009-11-10 M. S. Wheatland , F. J. Farvis

We investigate the three-dimensional structure of the pulsar magnetosphere through time-dependent numerical simulations of a magnetic dipole that is set in rotation. We developed our own Eulerian finite difference time domain numerical…

Astrophysics · Physics 2009-11-13 Constantinos Kalapotharakos , Ioannis Contopoulos

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

Magnetic field extrapolation is a fundamental tool to reconstruct the three-dimensional magnetic field above the solar photosphere. However, the prevalently used force-free field model might not be applicable in the lower atmosphere with…

Solar and Stellar Astrophysics · Physics 2023-07-12 Fu Yu , Jie Zhao , Yang Su , Xiaoshuai Zhu , Yang Guo , Jinhua Shen , Hui Li

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

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

(abridged) Pulsar activity and its related radiation mechanism are usually explained by invoking some plasma processes occurring inside the magnetosphere. Despite many detailed local investigations, the global electrodynamics around those…

High Energy Astrophysical Phenomena · Physics 2015-06-05 J. Pétri

The stationary axisymmetric force-free magnetosphere of a pulsar is considered. We present an exact dipolar solution of the pulsar equation, construct the magnetospheric model on its basis and examine its observational support. The new…

High Energy Astrophysical Phenomena · Physics 2016-08-30 S. A. Petrova

Besides their own intrinsic interest, correct interpretation of solar surface magnetic field observations is crucial to our ability to describe the global magnetic structure of the solar atmosphere. Photospheric magnetograms are often used…

Solar and Stellar Astrophysics · Physics 2010-10-29 Gordon J. D. Petrie , Irina Patrikeeva

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

Coupled flux transport and magneto-frictional simulations are extended to simulate the continuous magnetic field evolution in the global solar corona for over 15 years, from the start of Solar Cycle 23 in 1996. By simplifying the dynamics,…

Solar and Stellar Astrophysics · Physics 2015-06-15 A. R. Yeates

The potential field source surface (PFSS) equations are commonly used to model the coronal magnetic field of the Sun and other stars. As with any computational model, solving equations using a numerical scheme introduces errors due to…

Solar and Stellar Astrophysics · Physics 2022-01-20 David Stansby , Daniel Verscharen

We undertake a first attempt towards a consistent reconstruction of the coronal magnetic field and the coronal density structure. We consider a stationary solar corona which has to obey the equations of magnetohydrostatics. We solve these…

Astrophysics · Physics 2009-06-25 T. Wiegelmann , B. Inhester

Coronal magnetic fields evolve quasi statically over long time scales and dynamically over short time scales. As of now there exists no regular measurements of coronal magnetic fields, and therefore generating the coronal magnetic field…

Solar and Stellar Astrophysics · Physics 2023-12-20 P. Vemareddy , Jörn Warnecke , Ph. A. Bourdin

We numerically examine the exterior solution of spherically symmetric and static configuration in scalar-tensor theories by using the nonminimally coupled scalar field with zero potential as our sample model. Our main purpose in this work…

General Relativity and Quantum Cosmology · Physics 2023-03-20 A. Savaş Arapoğlu , Sermet Çağan , A. Emrah Yükselci

The magneto-frictional method is used in solar physics to compute both static and quasi-static models of the Sun's coronal magnetic field. Here, we examine how accurately magneto-friction (without fluid pressure) is able to predict the…

Solar and Stellar Astrophysics · Physics 2022-01-20 A. R. Yeates

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