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Stepwise changes of the photospheric magnetic field, which often becomes more horizontal, have been observed during many flares. Previous interpretations include coronal loops that contract and it has been speculated that such jerks could…

Solar and Stellar Astrophysics · Physics 2017-01-04 Lucia Kleint

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

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

Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously…

Solar and Stellar Astrophysics · Physics 2020-11-05 Zihao Yang , Hui Tian , Steven Tomczyk , Richard Morton , Xianyong Bai , Tanmoy Samanta , Yajie Chen

The study of magnetars is of particular relevance since these objects are the only laboratories where the physics in ultra-strong magnetic fields can be directly tested. Until now, spectroscopic and timing measurements at X-ray energies in…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Roberto Taverna , Fabio Muleri , Roberto Turolla , Paolo Soffitta , Sergio Fabiani , Luciano Nobili

We report in this letter our analysis of a large sample of photospheric vector magnetic field measurements. Our sample consists of 17200 vector magnetograms obtained from January 1997 to August 2004 by Huairou Solar Observing Station of the…

Astrophysics · Physics 2009-11-11 Mei Zhang

To make physics experiments more directly relevant to everyday life and help students realize how their smart phones or tablets can be used as sensors for scientific measurements, we designed two introductory physics experiments to measure…

Physics Education · Physics 2022-12-06 Glen D. Gillen , Katharina Gillen

We derive an analytical approximation of nonlinear force-free magnetic field solutions (NLFFF) that can efficiently be used for fast forward-fitting to solar magnetic data, constrained either by observed line-of-sight magnetograms and…

Solar and Stellar Astrophysics · Physics 2014-03-27 Markus J. Aschwanden

{Although there is considerable evidence supporting an ubiquitous magnetic field in solar/stellar photospheres, its impact in the determination of abundances has never been quantified. In this work we investigate whether the magnetic field…

Astrophysics · Physics 2009-11-13 J. M. Borrero

Early magnetographic observations indicated that magnetic field in the solar photosphere has unresolved small-scale structure. Near-infrared and optical data with extremely high spatial resolution show that these structures have scales of…

Solar and Stellar Astrophysics · Physics 2018-11-21 M. Gordovskyy. , S. Shelyag , P. K. Browning , V. G. Lozitsky

When time-reversal symmetry is broken on its surface, topological insulators exhibit a magnetoelectric response which is described by axion electrodynamics. A direct consequence of this theory is the appearance of a magnetic field that…

Mesoscale and Nanoscale Physics · Physics 2020-01-08 A. Martín-Ruiz , Omar Rodríguez-Tzompantzi , J. R. Maze , L. F. Urrutia

Using turbulent MHD simulations (magnetic Reynolds numbers up to 8000) and Hinode observations, we study effects of turbulence on measuring the solar magnetic field outside active regions. Firstly, from synthetic Stokes V profiles for the…

Astrophysics · Physics 2011-02-11 Jonathan Pietarila Graham , Sanja Danilovic , Manfred Schuessler

Expanding on an earlier work that relied on linear force-free magnetic fields, we self-consistently derive the instantaneous free magnetic energy and relative magnetic helicity budgets of an unknown three-dimensional nonlinear force-free…

Solar and Stellar Astrophysics · Physics 2015-06-11 M. K. Georgoulis , K. Tziotziou , N. -E. Raouafi

The evolution of nonpotential characteristics of magnetic fields in AR 5747 is presented using Mees Solar Observatory magnetograms taken on Oct. 20, 1989 to Oct. 22, 1989. The active region showed such violent flaring activities during the…

Astrophysics · Physics 2007-05-23 Y. -J. Moon , H. S. Yun , G. S. Choe , Y. D. Park , D. L. Mickey

The relation between the intensity of chromospheric emissions and the photospheric magnetic field strength has been examined in several studies, but the effect of the magnetic field inclination on chromospheric emissions remains almost…

Solar and Stellar Astrophysics · Physics 2024-09-27 Ismo Tähtinen , Alexei A. Pevtsov , Timo Asikainen , Kalevi Mursula

To make certain quantitative interpretations of spectra from NMR experiments carried out on heterogeneous samples, such as cells and tissues, we must be able to estimate the magnetic and electric fields experienced by the resonant nuclei of…

Chemical Physics · Physics 2007-05-23 C. J. Durrant , M. P. Hertzberg , P. W. Kuchel

Getting insights into the 3D structure of the solar coronal magnetic field have been done in the past by two completely different approaches: (1.) Nonlinear force-free field (NLFFF) extrapolations, which use photospheric vector magnetograms…

Solar and Stellar Astrophysics · Physics 2017-09-20 Iulia Chifu , Thomas Wiegelmann , Bernd Inhester

The structure of the photospheric magnetic field during solar flares is examined using echelle spectropolarimetric observations. The study is based on several Fe I and Cr I lines observed at locations corresponding to brightest H$\alpha$…

Solar and Stellar Astrophysics · Physics 2015-06-19 Mykola Gordovskyy , Vsevolod G. Lozitsky

The possibility of measuring the post-Newtonian gravitoelectric correction to the orbital period of a test particle freely orbiting a spherically symmetric mass in the Solar System is analyzed. It should be possible, in principle, to detect…

General Relativity and Quantum Cosmology · Physics 2012-07-31 Lorenzo Iorio

Solar activity can be witnessed in the form of sunspots and active regions, where the magnetic field is enhanced by up to a factor 1000 as compared to that of the quiet Sun. In addition, solar activity manifests itself in terms of flares,…

Solar and Stellar Astrophysics · Physics 2025-07-25 Gottfried Mann , Frédéric Schuller