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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

Predicting the severity of the solar eruptive phenomena like flares and Coronal Mass Ejections (CMEs) remains a great challenge despite concerted efforts for several decades. The advent of high quality vector magnetograms obtained from…

Solar and Stellar Astrophysics · Physics 2015-05-19 Sanjiv Kumar Tiwari , P. Venkatakrishnan , Sanjay Gosain

We used magnetograms acquired with the {\it Helioseismic and Magnetic Imager} (HMI) on board the {\it Solar Dynamics Observatory} (SDO) to calculate and analyze spatial correlation functions and the multi-fractal spectra in solar active…

Solar and Stellar Astrophysics · Physics 2024-04-11 Valentina Abramenko , Regina Suleymanova

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

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

A statistical analysis of magnetic energies of the nonlinear force-free and potential fields, and their difference (a proxy for the free magnetic energy) in active regions (ARs) on the Sun of different Hale (Mount Wilson) and McIntosh…

Solar and Stellar Astrophysics · Physics 2025-04-15 I. V. Zimovets , I. N. Sharykin , W. -Q. Gan

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

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

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

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

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

Time series of photospheric magnetic parameters of solar active regions (ARs) are used to answer whether scaling properties of fluctuations embedded in such time series help to distinguish between flare-quiet and flaring ARs. We examine a…

Solar and Stellar Astrophysics · Physics 2020-10-21 Eo-Jin Lee , Sung-Hong Park , Yong-Jae Moon

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

Solar active regions (ARs) are crucial for understanding the long-term evolution of solar activities and predicting eruptive phenomena, including solar flares and coronal mass ejections. However, the cycle-dependent properties in the…

Solar and Stellar Astrophysics · Physics 2025-04-25 Yuxia Liu , Tingting Xu , Miao Wan , Linhua Deng , Xinhua Zhao , Shiyang Qi , Nanbin Xiang , Weihong Zhou

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

In our earlier study of this series (Park et al. 2020, Paper I), we examined the hemispheric sign preference (HSP) of magnetic helicity flux $dH/dt$ across photospheric surfaces of 4802 samples of 1105 unique active regions (ARs) observed…

Solar and Stellar Astrophysics · Physics 2021-04-28 Sung-Hong Park , K. D. Leka , Kanya Kusano

Until now, how the magnetic fields in M/X-class flaring active regions (ARs) differ from C-class flaring ARs remains unclear. Here, we calculate the key magnetic field parameters within the area of high photospheric free energy density (HED…

Solar and Stellar Astrophysics · Physics 2024-03-01 Ting Li , Yanfang Zheng , Xuefeng Li , Yijun Hou , Xuebao Li , Yining Zhang , Anqin Chen

Solar active regions (ARs) that produce major flares typically exhibit strong plasma shear flows around photospheric magnetic polarity inversion lines (MPILs). It is therefore important to quantitatively measure such photospheric shear…

Solar and Stellar Astrophysics · Physics 2018-10-29 Sung-Hong Park , Jordan A. Guerra , Peter T. Gallagher , Manolis K. Georgoulis , D. Shaun Bloomfield

In this study we present the study of solar active regions based on BOAO vector magnetograms and $H\alpha$ filtergrams. With the new calibration method we analyzed BOAO vector magnetograms taken from the SOFT observational system to compare…

Astrophysics · Physics 2007-05-23 Y. -J. Moon , Y. D. Park , H. S. Yun , E. -A. Cho

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
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