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We study five sequential solar flares (SOL2015-08-07) occurring in Active Region 12396 observed with the Goode Solar Telescope (GST) at the BBSO, complemented by IRIS and SDO observations. The main flaring region is an arch filament system…

Solar and Stellar Astrophysics · Physics 2018-03-19 Yingna Su , Rui Liu , Shangwei Li , Wenda Cao , Kwangsu Ahn , Haisheng Ji

Here, we analyzed magnetic elements of the solar active regions (ARs) observed in the line-of-sight magnetograms (the 6173 \AA~Fe \small{I} line) recorded with the Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI). The…

Solar and Stellar Astrophysics · Physics 2021-09-28 M. A. Moradhaseli , M. Javaherian , N. Fathalian , H. Safari

Here, we developed a complex network of solar active regions (ARs) to study various local and global properties of the network. The values of the Hurst exponent ($0.8-0.9$) were evaluated by both the detrended fluctuation analysis and the…

Solar and Stellar Astrophysics · Physics 2017-08-23 Farhad Daei , Hossein Safari , Neda Dadashi

Identifying solar active regions (ARs), which consist of one or more pairs of magnetic patches with opposite polarities, is essential due to their significant role in dynamic solar atmospheric phenomena. In this study, we analyze ARs during…

Solar and Stellar Astrophysics · Physics 2025-09-16 Zahra Tajik , Hasan Rezaei , Mehdi Simiari , Hossien Safari

Solar eruptive phenomena, like flares and coronal mass ejections(CMEs) are governed by magnetic fields. To describe the structure of these phenomena one needs information on the magnetic flux density and the electric current density vector…

Solar and Stellar Astrophysics · Physics 2015-06-17 Tilaye Tadesse , T. Wiegelmann , Pevtsov A Alexei , P. Macneice , S. Gosain

Context: Solar active regions (ARs) are key manifestations of the Sun's magnetic activity, displaying diverse spatial and temporal characteristics. Their formation and evolution play a crucial role in understanding the solar dynamo and…

Solar and Stellar Astrophysics · Physics 2025-08-06 M. Švanda , J. Jurčák , M. Schmassmann

We analyse the topology of photospheric magnetic fields and sub-photospheric flows of several active regions (ARs) that are observed during the peak to descending phase of the solar cycle 23. Our analysis shows clear evidence of hemispheric…

Solar and Stellar Astrophysics · Physics 2020-08-12 R. A. Maurya , A. Ambastha

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

Using a recently suggested magneto-morphological classification (MMC, Abramenko, 2021, MNRAS Vol 507) of solar active regions (ARs), we explored 3048 ARs, observed from12 May 1996 to 27 December 2021. Magnetograms were acquired with the…

Solar and Stellar Astrophysics · Physics 2026-01-21 Anastasiya Zhukova , Valentina Abramenko

Solar active regions (ARs) are the places hosting the majority of solar eruptions. Studying the evolution and morphological features of ARs is not only of great significance to the understanding of the physical mechanisms of solar…

Solar and Stellar Astrophysics · Physics 2025-02-26 Ruishuo Chen , Wutong Lu , Qi Hao , Yifan Meng , Pengfei Chen , Chenxi Shi

Coronal electric currents store the magnetic energy that is released in solar flares and coronal mass ejections (CMEs). Here, we use photospheric vector magnetic field observations to study currents in active regions 10930 and 11158, which…

Solar and Stellar Astrophysics · Physics 2025-08-27 Brian T. Welsch

Aims. Although the temporal evolution of active regions (ARs) is relatively well understood, the processes involved continue to be the subject of investigation. We study how the magnetic field of a series of ARs evolves with time to better…

Using solar vector magnetograms of the highest available spatial resolution and signal-to-noise ratio we perform a detailed study of electric current patterns in two solar active regions: a flaring/eruptive, and a flare-quiet one. We aim to…

Solar and Stellar Astrophysics · Physics 2015-06-11 Manolis K. Georgoulis , Viacheslav S. Titov , Zoran Mikic

[..] The change in the magnetic configuration due to the increase/decrease of electric current for different force-free models (potential, linear and nonlinear force-free fields) has never been studied in detail before. Here we focus…

Solar and Stellar Astrophysics · Physics 2015-05-28 S. Regnier

We have analyzed multi-wavelength observations and magnetic-field data for the solar flare of May 10, 2012 (04:18 UT) and have detected a sign inversion of the signal in the line-of-sight magnetic measurements in the umbra of a small spot.…

Solar and Stellar Astrophysics · Physics 2016-10-19 M. A. Livshits , I. Yu. Grigoryeva , I. I. Myshyakov , G. V. Rudenko

Typical solar flares display two quasi-parallel, bright ribbons on the chromosphere. In between is the polarity inversion line (PIL) separating concentrated magnetic fluxes of opposite polarity in active regions (ARs). Intriguingly a series…

Solar and Stellar Astrophysics · Physics 2016-09-30 Rui Liu , Jun Chen , Yuming Wang , Kai Liu

Solar active regions are driven dissipative dynamical systems. The turbulent convection zone forces new magnetic flux tubes to rise above the photosphere and shuffles the magnetic fields which are already above the photosphere. The driven…

Astrophysics · Physics 2009-09-29 Loukas Vlahos

Observational pre-cursors of large solar flares provide a basis for future operational systems for forecasting. Here, we study the evolution of the normalized emergence (EM), shearing (SH) and total (T) magnetic helicity flux components for…

Solar and Stellar Astrophysics · Physics 2022-02-09 Sz. Soós , M. B. Korsós , H. Morgan , R. Erdélyi

We compare the coronal magnetic energy and helicity of two solar active regions (ARs), prolific in major eruptive (AR~11158) and confined (AR~12192) flaring, and analyze the potential of deduced proxies to forecast upcoming flares. Based on…

Solar and Stellar Astrophysics · Physics 2020-01-08 J. K. Thalmann , K. Moraitis , L. Linan , E. Pariat , G. Valori , K. Dalmasse

We continue our attempt to connect observational data on current helicity in solar active regions with solar dynamo models. In addition to our previous results about temporal and latitudinal distributions of current helicity (Kleeorin et…

Astrophysics · Physics 2009-11-10 H. Zhang , D. Sokoloff , I. Rogachevskii , D. Moss , V. Lamburt , K. Kuzanyan , N. Kleeorin