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We present the first part of a project on the global energetics of solar flares and coronal mass ejections (CMEs) that includes about 400 M- and X-class flares observed with AIA and HMI onboard SDO. We calculate the potential energy, free…

Solar and Stellar Astrophysics · Physics 2014-12-02 Markus J. Aschwanden , Yan Xu , Ju Jing

We report the evolution of magnetic field and its energy in NOAA active region 11158 over 5 days based on a vector magnetogram series from the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO). Fast flux…

Solar and Stellar Astrophysics · Physics 2016-06-30 Xudong Sun , J. Todd Hoeksema , Yang Liu , Thomas Wiegelmann , Keiji Hayashi , Qingrong Chen , Julia Thalmann

Solar flares are driven by release of free magnetic energy and often associated with restructurization of the magnetic field topology. Yet, observations of evolving magnetic field in the flaring volume are limited to very few cases…

Solar and Stellar Astrophysics · Physics 2026-02-18 Gregory D. Fleishman , Tatyana Kaltman , Sijie Yu

We study the coronal magnetic field structure inside active regions and its temporal evolution. We attempt to compare the magnetic configuration of an active region in a very quiet period with that for the same region during a flare.…

Astrophysics · Physics 2009-11-13 J. K. Thalmann , T. Wiegelmann , N. -E. Raouafi

We report the discovery of torsional Alfv\'enic oscillations in solar flares, which modulate the time evolution of the magnetic free energy $E_f(t)$, while the magnetic potential energy $E_p(t)$ is uncorrelated, and the nonpotential energy…

Solar and Stellar Astrophysics · Physics 2021-06-14 Markus J. Aschwanden , Tongjiang Wang

We aim to better characterize the conditions of the solar corona, especially with respect to the occurrence of confined and eruptive flares. In this work, we model the coronal evolution around 231 large flares observed during solar cycle…

Solar and Stellar Astrophysics · Physics 2025-01-29 Julia K. Thalmann , Manu Gupta , Astrid M. Veronig , Yang Liu

Magnetic free energy powers solar flares and coronal mass ejections (CMEs), and the buildup of magnetic helicity might play a role in the development of unstable structures that subsequently erupt. To better understand the roles of energy…

Solar and Stellar Astrophysics · Physics 2022-11-21 Yang Liu , Brian T. Welsch , Gherardo Valori , Manolis K. Georgoulis , Yang Guo , Etienne Pariat , Sung-Hong Park , Julia K. Thalmann

We perform a detailed study of the energetics for a well-observed solar eruption and flare that occurred on 28 October 2021. This event included a GOES class X1.0 flare, a global EUV wave, and a coronal mass ejection that reached speeds of…

We explore the processes of repetitive build-up and explosive release of magnetic energy together with the formation of magnetic flux ropes that eventually resulted into three homologous eruptive flares of successively increasing…

Solar and Stellar Astrophysics · Physics 2023-02-08 Suraj Sahu , Bhuwan Joshi , Avijeet Prasad , Kyung-Suk Cho

We investigate the plasma and magnetic environment of active region NOAA 11261 on 2 August 2011 around a GOES M1.4 flare/CME (SOL2011-08-02T06:19). We compare coronal emission at (extreme) ultraviolet and X-ray wavelengths, using SDO AIA…

Solar and Stellar Astrophysics · Physics 2016-08-03 Julia K. Thalmann , Astrid M. Veronig , Yang Su

The cause of excess spectral line broadening (non-thermal velocity) is not definitively known, but given its rise before and during flaring, the causal processes hold clues to understanding the triggers for the onset of reconnection and the…

Solar and Stellar Astrophysics · Physics 2024-01-23 James McKevitt , Robert Jarolim , Sarah Matthews , Deborah Baker , Manuela Temmer , Astrid Veronig , Hamish Reid , Lucie Green

A more accurate analytical solution of the {\sl vertical-current approximation nonlinear force-free field (VCA3-NLFFF)} model is presented that includes besides the radial $(B_r)$ and the azimuthal $(B_\varphi)$ magnetic field components a…

Solar and Stellar Astrophysics · Physics 2020-01-08 Markus J. Aschwanden

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

The 2003 October 28 (X17.2) eruptive flare was a unique event. The coronal electric field and the {\pi}-decay {\gamma}-ray emission flux had the highest values ever inferred in solar flares. This study reveals physical links between the…

A subclass of early impulsive solar flares, cold flares, was proposed to represent a clean case, where the release of the free magnetic energy (almost) entirely goes to acceleration of the nonthermal electrons, while the observed thermal…

Solar and Stellar Astrophysics · Physics 2025-08-27 Gregory D. Fleishman , Galina G. Motorina , Sijie Yu , Gelu M. Nita

It is well known that photospheric flux emergence is an important process for stressing coronal fields and storing magnetic free energy, which may then be released during a flare. The \emph{Helioseismic and Magnetic Imager} (HMI) onboard…

Solar and Stellar Astrophysics · Physics 2015-06-15 Lucas A. Tarr , Dana W. Longcope , Margaret Millhouse

We examine a simulation of flux emergence and cancellation, which shows a complex sequence of processes that accumulate free magnetic energy in the solar corona essential for the eruptive events such as coronal mass ejections (CMEs),…

Solar and Stellar Astrophysics · Physics 2015-06-05 Fang Fang , Ward Manchester , William P. Abbett , Bart van der Holst

Solar flares are powered by energy stored in the coronal magnetic field, a portion of which is released when the field reconfigures into a lower energy state. Investigation of sunspot magnetic field topology during flare activity is useful…

Solar and Stellar Astrophysics · Physics 2015-03-10 Sophie A. Murray , D. Shaun Bloomfield , Peter T. Gallagher

This paper presents measurements of the energy radiated by the lower solar atmosphere, at optical, UV, and EUV wavelengths, during an X-class solar flare (SOL2011-02-15T01:56) in response to an injection of energy assumed to be in the form…

We present observations of electron energization in magnetic reconnection outflows during the pre-impulsive phase of solar flare SOL2012-07-19T05:58. During a time-interval of about 20 minutes, starting 40 minutes before the onset of the…

Solar and Stellar Astrophysics · Physics 2019-03-06 Marina Battaglia , Eduard P. Kontar , Galina Motorina
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