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The observed magnetic field on the solar surface is characterized by a very complex spatial and temporal behaviour. Although feature-tracking algorithms have allowed us to deepen our understanding of this behaviour, subjectivity plays an…

Solar and Stellar Astrophysics · Physics 2016-07-04 A. Y. Gorobets , J. M. Borrero , S. Berdyugina

Solar flares are intense bursts of electromagnetic radiation, which occur due to a rapid destabilization and reconnection of the magnetic field. While pre-flare signatures and trends have been investigated from magnetic observations prior…

Solar and Stellar Astrophysics · Physics 2025-06-18 Kara L. Kniezewski , Emily I. Mason , Daniel J. Emmons , Kyle E. Fitch , Seth H. Garland

We test the effects of magnetic fields on the mass determination of galaxy clusters with the X-ray method. As this method takes into account only thermal pressure, additional non-thermal pressure support, e.g. caused by a magnetic field,…

Astrophysics · Physics 2007-05-23 Klaus Dolag , Sabine Schindler

Force-free electrodynamics is the theoretical paradigm used to describe electromagnetic fields in a region where the inertia of plasma is negligible compared to the strength of the electromagnetic field. While these fields are studied…

General Relativity and Quantum Cosmology · Physics 2024-03-18 Rakshak Adhikari , Govind Menon , Mikhail V. Medvedev

We present the photospheric energy density of magnetic fields in two solar active regions inferred from observational vector magnetograms, and compare it with the possible different defined energy parameters of magnetic fields in the…

Solar and Stellar Astrophysics · Physics 2016-12-12 Hongqi Zhang

The vector magnetic field characteristics of superactive regions (SARs) hold the key for understanding why SARs are extremely active and provide the guidance in space weather prediction. We aim to quantify the characteristics of SARs using…

Solar and Stellar Astrophysics · Physics 2015-06-05 A. Q. Chen , J. X. Wang

The magnetic field governs the corona; hence it is a crucial parameter to measure. Unfortunately, existing techniques for estimating its strength are limited by strong assumptions and limitations. These techniques include photospheric or…

Solar and Stellar Astrophysics · Physics 2022-10-26 Juan Martinez-Sykora , Viggo H. Hansteen , Bart De Pontieu , Enrico Landi

A statistical study is carried out on the photospheric magnetic nonpotentiality in solar active regions and its relationship with associated flares. We select 2173 photospheric vector magnetograms from 1106 active regions observed by the…

Solar and Stellar Astrophysics · Physics 2012-08-10 Xiao Yang , HongQi Zhang , Yu Gao , Juan Guo , GangHua Lin

Our aim is to model the 3D magnetic field structure of the upper solar atmosphere, including regions of non-negligible plasma beta. We use high-resolution photospheric magnetic field measurements from SUNRISE/IMaX as boundary condition for…

Solar and Stellar Astrophysics · Physics 2015-12-09 T. Wiegelmann , T. Neukirch , D. H. Nickeler , S. K. Solanki , V. Martinez Pillet , J. M. Borrero

Magnetic fields dominate most solar activities, there exist direct relations between solar flare and the distributions of magnetic field, and also its corresponding magnetic energy. In this paper, the statistical results about the…

Solar and Stellar Astrophysics · Physics 2019-02-03 Suo Liu

We assess the validity of the free magnetic energy - relative magnetic helicity diagram for solar magnetic structures. We used two different methods of calculating the free magnetic energy and the relative magnetic helicity budgets: a…

Solar and Stellar Astrophysics · Physics 2014-10-15 K. Tziotziou , K. Moraitis , M. K. Georgoulis , V. Archontis

The longitudinal asymmetry of the photospheric magnetic field distribution is studied on the basis of the data of the Kitt Peak National Solar Observatory (synoptic maps for the period 1976 - 2016). The method of vector summing of magnetic…

Solar and Stellar Astrophysics · Physics 2019-04-08 D. G. Baranov , E. S. Vernova , M. I. Tyasto , O. A. Danilova

A magnetic power spectral analysis is performed on 53 solar active regions, observed from August 2011 to July 2012. Magnetic field data obtained from the Helioseismic and Magnetic Imager, inverted as Active Region Patches, are used to study…

Solar and Stellar Astrophysics · Physics 2016-12-28 Revati S. Mandage , R. T. James McAteer

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 test a nonlinear force-free field (NLFFF) optimization code in spherical geometry using an analytical solution from Low and Lou. Several tests are run, ranging from idealized cases where exact vector field data are provided on all…

Solar and Stellar Astrophysics · Physics 2015-06-11 Y. Guo , M. D. Ding , Y. Liu , X. D. Sun , M. L. DeRosa , T. Wiegelmann

The consequences of considering the measure of integration in the action to be defined by degrees of freedom independent of the metric are studied. Models without the cosmological constant problem, new ways of spontaneously breaking scale…

High Energy Physics - Theory · Physics 2007-05-23 E. I. Guendelman

For all involved in astronomy, the importance of monitoring and determining astrophysical magnetic field strengths is clear. It is also a well-known fact that the corona magnetic fields play an important part in the origin of solar flares…

Atomic Physics · Physics 2020-08-18 Ran Si , Tomas Brage , Wenxian Li , Jon Grumer , Meichun Li , Roger Hutton

The design and later use of modern spectropolarimeters and magnetographs require a number of tolerance specifications that allow the developers to build the instrument and then the scientists to interpret the data accuracy. Such…

Solar and Stellar Astrophysics · Physics 2015-06-05 J. C. del Toro Iniesta , V. Martínez Pillet

The field of a uniformly magnetized rotating sphere is studied with special attention to the surface where the electric and magnetic fields are orthogonal to each other. The equation of this surface, valid at arbitrary distances from the…

High Energy Astrophysical Phenomena · Physics 2015-10-27 V. Epp , M. A. Masterova

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
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