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Related papers: Coronal magnetic field evolution over the cycle 24

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Two sequences of solar images obtained by the Transition Region and Coronal Explorer in three UV passbands are studied using wavelet and Fourier analysis and compared to the photospheric magnetic flux measured by the Michelson Doppler…

The rapid, irreversible change of the photospheric magnetic field has been recognized as an important element of the solar flare process. This Letter reports such a rapid change of magnetic fields during the 2011 February 13 M6.6 flare in…

Solar and Stellar Astrophysics · Physics 2015-06-03 Chang Liu , Na Deng , Rui Liu , Jeongwoo Lee , Thomas Wiegelmann , Ju Jing , Yan Xu , Shuo Wang , Haimin Wang

We study extreme-ultraviolet emission line spectra derived from three-dimensional magnetohydrodynamic models of structures in the corona. In order to investigate the effects of increased magnetic activity at photospheric levels in a…

Solar and Stellar Astrophysics · Physics 2009-04-16 Pia Zacharias , Sven Bingert , Hardi Peter

We describe the characteristics and evolution of the magnetic field and chromospheric emission in an active region core observed by the Solar Optical Telescope on Hinode. Consistent with previous studies, we find that the moss is unipolar,…

Solar and Stellar Astrophysics · Physics 2015-05-19 David H. Brooks , Harry P. Warren , Amy R. Winebarger

The distribution of magnetic flux across the solar photosphere results in a complex web of coronal magnetic field structures. To understand this complexity, the magnetic skeleton of the coronal field can be calculated. The skeleton…

Solar and Stellar Astrophysics · Physics 2014-06-23 Sarah J. Platten , Clare E. Parnell , Andrew L. Haynes , Eric R. Priest , Duncan H. Mackay

To estimate the hemispheric flux generation rate of the large-scale radial magnetic field in the Solar Cycles 23 and 24, we use the photospheric observations of the solar magnetic fields and results of the mean-field dynamo models. Results…

Solar and Stellar Astrophysics · Physics 2024-08-12 V. V. Pipin

Nonlinear force-free field (NLFFF) models are thought to be viable tools for investigating the structure, dynamics and evolution of the coronae of solar active regions. In a series of NLFFF modeling studies, we have found that NLFFF models…

The concept of surface-flux transport (SFT) is commonly used in evolving models of the large-scale solar surface magnetic field. These photospheric models are used to determine the large-scale structure of the overlying coronal magnetic…

Solar and Stellar Astrophysics · Physics 2023-04-12 Graham Barnes , Marc L. DeRosa , Shaela I. Jones , Charles N. Arge , Carl J. Henney , Mark C. M. Cheung

We study the asymmetric distribution of weak photospheric magnetic field values in the two hemispheres separately using synoptic maps from SDO/HMI, SOLIS/VSM and WSO during solar cycles 21-24. We calculate the weak-field asymmetry (shift)…

Solar and Stellar Astrophysics · Physics 2019-10-09 Tibebu Getachew , Ilpo Virtanen , Kalevi Mursula

Context: Knowledge about the coronal magnetic field is important to the understanding the structure of the solar corona. We compute the field in the higher layers of the solar atmosphere from the measured photospheric field under the…

Solar and Stellar Astrophysics · Physics 2014-11-20 T. Tadesse , T. Wiegelmann , B. Inhester

The regular observation of the solar magnetic field is available only for about last five cycles. Thus, to understand the origin of the variation of the solar magnetic field, it is essential to reconstruct the magnetic field for the past…

Analysis of synoptic data from the Vector Stokes Magnetograph (VSM) of the Synoptic Optical Long-term Investigations of the Sun (SOLIS) and the NASA/NSO Spectromagnetograph (SPM) at the NSO/Kitt Peak Vacuum Telescope facility shows that the…

Solar and Stellar Astrophysics · Physics 2016-02-09 Alexander V. Mordvinov , Alexei A. Pevtsov , Luca Bertello , Gordon J. D. Petrie

The line-of-sight (LOS) component of the large-scale photospheric magnetic field has been observed since the 1950s, but the daily full-disk observations of the full vector magnetic field started only in 2010 using the SOLIS Vector Stokes…

Space Physics · Physics 2019-04-25 Ilpo I. Virtanen , Alexei A. Pevtsov , Kalevi Mursula

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…

Extrapolation codes in Cartesian geometry for modelling the magnetic field in the corona do not take the curvature of the Sun's surface into account and can only be applied to relatively small areas, e.g., a single active region. We compare…

Solar and Stellar Astrophysics · Physics 2015-06-11 Tilaye Tadesse , T. Wiegelmann , B. Inhester , P. MacNeice , A. Pevtsov , X. Sun

On the base of the solar magnetic field measurements obtained in Stanford in 1976--2003 the properties of the cyclic evolution of the large-scale magnetic field are investigated. Some regularities are found in longitudinal and latitudinal…

Astrophysics · Physics 2007-05-23 R. N. Ikhsanov , V. G. Ivanov

The interaction of magnetic fields and convection is investigated in the context of the coronal heating problem. We study the motions of photospheric magnetic elements using filtergrams obtained at the Swedish Vacuum Solar Telescope at La…

In this study, photospheric vector magnetograms obtained with the Synoptic Optical Long-term Investigations of the Sun survey (SOLIS), are used as boundary conditions to model the three-dimensional nonlinear force-free (NLFF) coronal…

Solar and Stellar Astrophysics · Physics 2015-05-30 Tilaye Tadesse , T. Wiegelmann , B. Inhester , A. Pevtsov

With the development of new instrumentation providing measurements of solar photospheric vector magnetic fields, we need to develop our understanding of the effects of current density on coronal magnetic field configurations. The object is…

Astrophysics · Physics 2009-11-13 S. Regnier , E. R. Priest