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We study the role of rotating sunspots in relation to the evolution of various physical parameters characterizing the non-potentiality of the active region NOAA 11158 and its eruptive events using the magnetic field data from the…

Solar and Stellar Astrophysics · Physics 2015-06-11 P. Vemareddy , A. Ambastha , R. A. Maurya

A process of diffusion of small-scale magnetic elements inside four active regions (ARs) was analyzed. Line-of-sight magnetograms acquired by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamic Observatory (SDO) during a…

Solar and Stellar Astrophysics · Physics 2018-12-14 Valentina I. Abramenko

The solar-stellar connection provides a unique framework for understanding magnetic activity and atmospheric heating across a broad spectrum of stars. Solar Dynamics Observatory (SDO) of NASA, equipped with the Helioseismic and Magnetic…

Solar and Stellar Astrophysics · Physics 2026-02-20 Shin Toriumi

We report a systematic strengthening of the local solar surface or fundamental $f$-mode $1$-$2$ days prior to the emergence of an active region (AR) in the same (corotating) location. Except for a possibly related increase in the kurtosis…

Solar and Stellar Astrophysics · Physics 2016-11-23 Nishant K. Singh , Harsha Raichur , Axel Brandenburg

We present an automated system for detecting, tracking, and cataloging emerging active regions throughout their evolution and decay using SOHO Michelson Doppler Interferometer (MDI) magnetograms. The SolarMonitor Active Region Tracking…

Solar and Stellar Astrophysics · Physics 2010-07-01 Paul A. Higgins , Peter T. Gallagher , R. T. James McAteer , D. Shaun Bloomfield

We calculated the 3D distribution of the area expansion factors in a potential magnetic field extrapolated from the high-resolution \textit{Hinode}/SOT magnetogram of a quiescent active region NOAA 11482. Retaining only closed loops within…

Solar and Stellar Astrophysics · Physics 2015-06-23 Jaroslav Dudik , Elena Dzifcakova , Jonathan W. Cirtain

Due to their characteristic temperature and density, loop structures in active regions (ARs) can be seen bright in extreme ultraviolet (EUV) and soft X-ray images. The semiempirical determination of the three-dimensional (3D) distribution…

Solar and Stellar Astrophysics · Physics 2020-12-16 F. A. Nuevo , C. Mac Cormack , M. López Fuentes , A. M. Vásquez , C. H. Mandrini

Light bridges, the bright structures that divide the umbra of sunspots and pores into smaller pieces, are known to produce wide variety of activity events in solar active regions (ARs). It is also known that the light bridges appear in the…

Solar and Stellar Astrophysics · Physics 2015-10-07 Shin Toriumi , Yukio Katsukawa , Mark C. M. Cheung

Magnetohydrodynamics of the solar corona is simulated numerically. The simulation is initialized with an extrapolated non-force-free magnetic field using the vector magnetogram of the active region (AR) NOAA 12192 obtained on the solar…

Solar and Stellar Astrophysics · Physics 2018-06-26 A. Prasad , R. Bhattacharyya , Qiang Hu , Sanjay Kumar , Sushree S. Nayak

The magnetic non-potentiality is important for understanding flares and other solar activities in active regions (ARs). Five non-potential parameters, i.e., electric current, current helicity, source field, photospheric free energy, and…

Solar and Stellar Astrophysics · Physics 2015-06-11 Qiao Song , Jun Zhang , Shuhong Yang , Yang Liu

Recent studies show that active-region (AR) upflowing plasma, observed by the EUV-Imaging Spectrometer (EIS), onboard Hinode, can gain access to open field-lines and be released into the solar wind (SW) via magnetic-interchange reconnection…

Solar and Stellar Astrophysics · Physics 2015-06-23 C. H. Mandrini , F. A. Nuevo , A. M. Vásquez , P. Démoulin , L. van Driel-Gesztelyi , D. Baker , J. L. Culhane , G. D. Cristiani , M. Pick

The topology and dynamics of the three-dimensional magnetic field in the solar atmosphere govern various solar eruptive phenomena and activities, such as flares, coronal mass ejections, and filaments/prominences. We have to observe and…

Solar and Stellar Astrophysics · Physics 2017-06-20 Yang Guo , Xin Cheng , M. D. Ding

The well-observed acoustic halo is an enhancement in time-averaged Doppler velocity and intensity power with respect to quiet-sun values which is prominent for weak and highly inclined field around the penumbra of sunspots and active…

Solar and Stellar Astrophysics · Physics 2016-01-27 Carlos Rijs , S. P. Rajaguru , Damien Przybylski , Hamed Moradi , Paul S. Cally , Sergiy Shelyag

We present a multiwavelength study of recurrent surges observed in H{\alpha}, UV (SOHO/EIT) and Radio (Learmonth, Australia) from the super-active region NOAA 10484 on 25 October, 2003. Several bright structures visible in H{\alpha} and UV…

Solar and Stellar Astrophysics · Physics 2015-06-04 Wahab Uddin , B. Schmieder , R. Chandra , Abhishek K. Srivastava , Pankaj Kumar , S. Bisht

Solar active regions (ARs) that produce strong flares and coronal mass ejections (CMEs) are known to have a relatively high non-potentiality and are characterized by delta-sunspots and sheared magnetic structures. In this study, we conduct…

Solar and Stellar Astrophysics · Physics 2017-11-29 Shin Toriumi , Shinsuke Takasao

Three-dimensional magnetic reconnection is a fundamental plasma process crucial for heating the solar corona and generating the solar wind, but resolving and characterizing it on the Sun remains challenging. Using high-quality data from the…

Magnetic field extrapolation is a fundamental tool to reconstruct the three-dimensional magnetic field above the solar photosphere. However, the prevalently used force-free field model might not be applicable in the lower atmosphere with…

Solar and Stellar Astrophysics · Physics 2023-07-12 Fu Yu , Jie Zhao , Yang Su , Xiaoshuai Zhu , Yang Guo , Jinhua Shen , Hui Li

Magnetic field data provided by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory were utilized to explore the changes in the magnetic energy of four active regions (ARs) during their emergence. We found that at…

Solar and Stellar Astrophysics · Physics 2019-08-21 Olga K. Kutsenko , Alexander S. Kutsenko , Valentina I. Abramenko

One of the puzzling features of solar magnetism is formation of long-living compact magnetic structures; such as sunspots and pores, in the highly turbulent upper layer of the solar convective zone. We use realistic radiative 3D MHD…

Solar and Stellar Astrophysics · Physics 2015-05-18 I. N. Kitiashvili , A. G. Kosovichev , A. A. Wray , N. N. Mansour

In this review many of the well known tools for the analysis of Complex systems are used in order to study the global coupling of the turbulent convection zone with the solar atmosphere where the magnetic energy is dissipated explosively.…

Solar and Stellar Astrophysics · Physics 2016-11-03 Loukas Vlahos , Heinz Isliker
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