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We present results of a study of intermittency and multifractality of magnetic structures in solar active regions (ARs). Line-of-sight magnetograms for 214 ARs of different flare productivity observed at the center of the solar disk from…

Solar and Stellar Astrophysics · Physics 2010-12-08 Valentyna Abramenko , Vasyl Yurchyshyn

The effect of using two representations of the normal-to-surface magnetic field to calculate photospheric measures that are related to active region (AR) potential for flaring is presented. Several AR properties were computed using…

Solar and Stellar Astrophysics · Physics 2018-01-24 Jordan A. Guerra , Sung-H. Park , Ioannis Kontogiannis , Peter T. Gallagher , Manolis Georgoulis , D. Shaun Bloomfield

Multiple recent investigations of solar magnetic field measurements have raised claims that the scale-free (fractal) or multiscale (multifractal) parameters inferred from the studied magnetograms may help assess the eruptive potential of…

Solar and Stellar Astrophysics · Physics 2015-05-20 Manolis K. Georgoulis

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

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

Using magnetographic data provided by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, we analyzed the structure of magnetic fields and vertical electric currents in six active regions (ARs) with different level…

Solar and Stellar Astrophysics · Physics 2020-02-19 Yuriy A. Fursyak , Alexander S. Kutsenko , Valentina I. Abramenko

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

The power spectra of the fluctuation noise of the solar active region (AR) areas and magnetic fluxes sequentially observed in time contain information about their geometrical features and the related fundamental physical processes. These…

Solar and Stellar Astrophysics · Physics 2024-03-14 G. Dumbadze , B. M. Shergelashvili , M. L. Khodachenko , S. Poedts

Studying the hemispheric distribution of active regions (ARs) with different magnetic morphology may clarify the features of the dynamo process that is hidden under the photospheric level. The magnetic flux data for 3047 ARs from the CrAO…

Solar and Stellar Astrophysics · Physics 2024-07-10 A. Zhukova

A solar active region (AR) is a three-dimensional magnetic structure formed in the convection zone, whose property is fundamentally important for determining the coronal structure and solar activity when emerged. However, our knowledge on…

Solar and Stellar Astrophysics · Physics 2013-01-22 Georgios Chintzoglou , Jie Zhang

Photospheric vector magnetograms from Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory are utilized as the boundary conditions to extrapolate both non-linear force-free and potential magnetic fields in solar corona.…

Solar and Stellar Astrophysics · Physics 2015-06-19 J. T. Su , J. Jing , S. Wang , T. Wiegelmann , H. M. Wang

Magnetic fields in the solar corona are responsible for a wide range of phenomena. However, any direct measurements of the coronal magnetic fields are very difficult due to lack of suitable spectral lines, weak magnetic fields, and high…

Solar and Stellar Astrophysics · Physics 2013-10-28 P. Vemareddy , A. Ambastha , T. Wiegelmann

A solar active region (AR) that produces at least one M- or X-class major flare tends to produce multiple flares during its passage across the solar disk. It will be interesting if we can estimate how flare-productive a given major flaring…

Solar and Stellar Astrophysics · Physics 2018-12-12 Eo-Jin Lee , Sung-Hong Park , Yong-Jae Moon

Flare productivity varies among solar active regions (ARs). This study analyzed 20 ARs of contrasting sunspot areas and flare productivities to understand the super flare productivity of certain ARs. We used the flare index (FI) as an…

Solar and Stellar Astrophysics · Physics 2023-12-27 Suman K. Dhakal , Jie Zhang

We studied the low-frequency $\lesssim 0.5\;$h$^{-1}$ (long-period $\gtrsim 2\;$h) oscillations of active regions (ARs). The investigation is based on an analysis of a time series built from Solar Dynamics Observatory/Helioseismic and…

Solar and Stellar Astrophysics · Physics 2022-03-22 G. Dumbadze , B. M. Shergelashvili , S. Poedts , T. V. Zaqarashvili , M. Khodachenko , P. De Causmaecker

Data for 3046 solar active regions (ARs) observed since May 12, 1996 to December 27, 2021 were utilized to explore how the magnetic fluxes from ARs of different complexity follow the solar cycle. Magnetograms from the Michelson Doppler…

Solar and Stellar Astrophysics · Physics 2022-12-15 Valentina I. Abramenko , Regina A. Suleymanova , Anastasija V. Zhukova

Magnetograms acquired with the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) were used to calculate and analyze time variations of turbulence and multifractality in the photosphere during the…

Solar and Stellar Astrophysics · Physics 2025-06-04 Valentina Abramenko

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

Sequences of line-of-sight (LOS) magnetograms recorded by the Michelson-Doppler Imager are used to quantitatively characterize photospheric magnetic structure and evolution in three active regions that rotated across the Sun's disk during…

Solar and Stellar Astrophysics · Physics 2015-05-27 B. T. Welsch , S. Christe , J. M. McTiernan

Recent studies indicate that measurements of fractal and multifractal parameters of active regions (ARs) are not efficient tools to discriminate ARs on the basis of the flare activity, as well as to predict flare events. Attempting…

Solar and Stellar Astrophysics · Physics 2017-05-19 F. Giorgi , I. Ermolli , P. Romano , M. Stangalini , F. Zuccarello , S. Criscuoli
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