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Related papers: Evolution of helicity in NOAA 10923 over three con…

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We present a combined analysis of the applications of the weighted horizontal magnetic gradient (denoted as WG_M in Korsos et al., ApJ, 802, L21, 2015) method and the magnetic helicity tool (Berger & Field, JFM, 147, 133, 1984) employed for…

Solar and Stellar Astrophysics · Physics 2018-01-03 Yudong Ye , M. B. Korsos , R. Erdelyi

Solar atmosphere is a single system unified by the presence of large-scale magnetic fields. Topological changes in magnetic fields that occur in one place may have consequences for coronal heating and eruptions for other, even remote…

Solar and Stellar Astrophysics · Physics 2013-02-05 Alexei A. Pevtsov

The non-association of coronal mass ejections with high energetic flares is sparse. For this reason, the magnetic conditions required for the confinedness of major flares is a topic of active research. Using multi-instrument observations,…

Solar and Stellar Astrophysics · Physics 2023-07-05 N. Vasantharaju , F. Zuccarello , F. Ferrente , S. L. Guglielmino

We studied the developing conditions of sigmoid structure under the influence of magnetic non-potential characteristics of a rotating sunspot in the active region (AR) 12158. Vector magnetic field measurements from Helioseismic Magnetic…

Solar and Stellar Astrophysics · Physics 2016-09-28 P. Vemareddy , X. Cheng , B. Ravindra

Employing the high spatio-temporal Interface Region Imaging Spectrograph 1330 {\AA} observations, we investigated the jet-like features that occurred during the X8.2 class flare in NOAA active region (AR) 12673 on 2017 September 10. These…

Solar and Stellar Astrophysics · Physics 2018-12-11 Xiaohong Li , Jun Zhang , Shuhong Yang , Yijun Hou

Sunspots are regions of decreased brightness on the visible surface of the Sun (photosphere) that are associated with strong magnetic fields. They have been found to be locations associated with solar flares, which occur when energy stored…

Solar and Stellar Astrophysics · Physics 2013-01-24 Sophie A. Murray

Recently, we have developed a method useful for mapping large-scale horizontal velocity fields in the solar photosphere. The method was developed, tuned and calibrated using the synthetic data. Now, we applied the method to the series of…

Astrophysics · Physics 2009-11-13 Michal Svanda , Mirek Klvana , Michal Sobotka , Vaclav Bumba

Using a 3D non-linear mean-field solar dynamo model, we investigate the magnetic helicity flux and magnetic twist, and tilt parameters of bipolar magnetic regions (BMRs) emerging from the solar convection zone due to the magnetic buoyancy…

Solar and Stellar Astrophysics · Physics 2025-08-04 V. V. Pipin , Shangbin Yang , A. G. Kosovichev

We carry out a comprehensive investigation comparing the three-dimensional magnetic field restructuring, flare energy release, and the helioseismic response, of two homologous flares, the 2011 September 6 X2.1 (FL1) and September 7 X1.8…

Solar and Stellar Astrophysics · Physics 2015-06-22 Chang Liu , Na Deng , Jeongwoo Lee , Thomas Wiegelmann , Chaowei Jiang , Brian R. Dennis , Yang Su , Alina Donea , Haimin Wang

We investigate the evolution of subsurface flows during the emergence and the active phase of sunspot regions using the time-distance helioseismology analysis of the full-disk Dopplergrams from the Helioseismic and Magnetic Imager (HMI)…

Solar and Stellar Astrophysics · Physics 2024-12-25 Alexander G. Kosovichev , Viacheslav M. Sadykov

We analyze the complete chain of effects caused by a solar eruptive event in order to better understand the dynamic evolution of magnetic-field related quantities in interplanetary space, in particular that of magnetic flux and helicity. We…

Solar and Stellar Astrophysics · Physics 2023-01-11 J. K. Thalmann , M. Dumbovic , K. Dissauer , T. Podladchikova , G. Chikunova , M. Temmer , E. Dickson , A. M. Veronig

The variations of the 3-D coronal magnetic fields associated with the X3.4-class flare of active region 10930 are studied in this paper. The coronal magnetic field data are reconstructed from the photospheric vector magnetograms obtained by…

Solar and Stellar Astrophysics · Physics 2016-05-03 Han He , Huaning Wang , Yihua Yan , P. F. Chen , Cheng Fang

In this study, the non-potential magnetic field parameters of active region NOAA 9077 are investigated; this AR experienced a super-strong X5.7 solar flare. Using advanced extrapolation techniques, the 3D magnetic field structure from…

Solar and Stellar Astrophysics · Physics 2025-06-18 Liu Suo , Shahid Idrees , Liu Dian , Zeng Shuguang

I report observations of unusually strong photospheric and chromospheric velocity oscillations in and near the leading sunspot of NOAA 10781 on 03 July 2005. I investigate an impinging wave as a possible origin of the velocity pattern, and…

Solar and Stellar Astrophysics · Physics 2015-03-17 C. Beck

The structural property of the magnetic field in flare-bearing solar active regions (ARs) is one of the key aspects for understanding and forecasting solar flares. In this paper, we make a comparative analysis on the chirality and magnetic…

Solar and Stellar Astrophysics · Physics 2020-05-19 Han He , Huaning Wang , Yihua Yan , Bo Li , P. F. Chen

The active region NOAA 11158 produced the first X-class flare of Solar Cycle 24, an X2.2 flare at 01:44 UT on 2011 February 15. Here we analyze SDO/HMI magnetograms covering a 12-hour interval centered at the time of this flare. We describe…

Solar and Stellar Astrophysics · Physics 2015-03-13 G. J. D. Petrie

We investigate the evolution of coronal loop emission in the context of the coronal magnetic field topology. New modeling techniques allow us to investigate the magnetic field structure and energy release in active regions. Using these…

Solar and Stellar Astrophysics · Physics 2015-05-19 J. -Y. Lee , Graham Barnes , K. D. Leka , Katharine K. Reeves , K. E. Korreck , L. Golub , E. E. DeLuca

We investigated four major solar flare events that occurred in active regions NOAA 10930 (December 13 and 14, 2006) and NOAA 11158 (February 13 and 15, 2011) by using data observed by the Solar Optical Telescope (SOT) onboard the Hinode…

Solar and Stellar Astrophysics · Physics 2015-06-17 Y. Bamba , K. Kusano , T. T. Yamamoto , T. J. Okamoto

Using the 135-second cadence of the photospheric vector data provided by the Helioseismic and Magnetic Imager telescope on board the Solar Dynamic Observatory, we examined the time-evolution of magnetic helicity fluxes across the…

Solar and Stellar Astrophysics · Physics 2018-10-17 Yi Bi , Ying D Liu , Yanxiao Liu , Jiayan Yang , Zhe Xu , Kaifan JI

It has been found that photospheric magnetic fields can change in accordance with the three-dimensional magnetic field restructuring following solar eruptions. Previous studies mainly use vector magnetic field data taken for events near the…

Solar and Stellar Astrophysics · Physics 2016-06-08 Dandan Ye , Chang Liu , Haimin Wang