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We present a case study of an M4-class flare on 28 March 2022, near Solar Orbiter's first science perihelion (0.33 AU). Solar Orbiter was 83.5{\deg} west of the Sun-Earth line, making the event appear near the eastern limb, while…

We present results from X-ray imaging of high-aspect-ratio magnetic reconnection experiments driven at the National Ignition Facility. Two parallel, self-magnetized, elongated laser-driven plumes are produced by tiling 40 laser beams. A…

Magnetic reconnection plays an integral part in nearly all models of solar flares and coronal mass ejections (CMEs). The reconnection heats and accelerates the plasma, produces energetic electrons and ions, and changes the magnetic topology…

Solar and Stellar Astrophysics · Physics 2017-07-26 John C. Raymond , Silvio Giordano , Angela Ciaravella

Identifying the source of the material within coronal mass ejections (CMEs) and understanding CME onset mechanisms are fundamental issues in solar and space physics. Parameters relating to plasma composition, such as charge states and He…

Solar and Stellar Astrophysics · Physics 2020-09-09 Hui Fu , R. A. Harrison , J. A. Davies , LiDong Xia , XiaoShuai Zhu , Bo Li , ZhengHua Huang , D. Barnes

It is well known among the scientific community that solar flare activity often begins well before the main impulsive energy release. Our aim is to investigate the earliest phase of four distinct flares observed by Solar Orbiter/STIX and…

This paper presents a multiwavelength study of the M8.0 flare and its associated fast halo CME that originated from a bipolar active region NOAA 10759 on 2005 May 13. The source active region has a conspicuous sigmoid structure at TRACE 171…

We use coronal imaging observations with SDO/AIA, and Hinode/EIS spectral data, to explore the potential of narrow band EUV imaging data for diagnosing the presence of hot (T >~5MK) coronal plasma in active regions. We analyze observations…

Solar and Stellar Astrophysics · Physics 2015-06-04 Paola Testa , Fabio Reale

Archived high-resolution X-ray spectra in the 13~\AA\ to 22~\AA\ range from the Flat Crystal Spectrometer (FCS), an instrument on the Solar Maximum Mission operating in the 1980s, are analyzed with reference to nonflaring active regions,…

Solar and Stellar Astrophysics · Physics 2026-01-27 Kenneth J. H. Phillips , Barbara Sylwester , Janusz Sylwester

The study of the localized plasma conditions before the impulsive phase of a solar flare can help us understand the physical processes that occur leading up to the main flare energy release. Here, we present evidence of a hot X-ray onset…

Solar and Stellar Astrophysics · Physics 2020-12-02 Hugh S. Hudson , Paulo J. A. Simoes , Lyndsay Fletcher , Laura A. Hayes , Iain G. Hannah

Solar flares are major space weather events that result from the explosive conversion of stored magnetic energy into bulk motion, plasma heating, and particle acceleration. While the standard flare model has proven highly successful in…

Solar and Stellar Astrophysics · Physics 2025-10-09 Joel T. Dahlin , Spiro K. Antiochos , Peter F. Wyper , Jiong Qiu , C. Richard DeVore

The energy released during solar flares is believed to be stored in non-potential magnetic fields associated with electric currents flowing in the corona. While no measurements of coronal electric currents are presently available, maps of…

Solar and Stellar Astrophysics · Physics 2015-08-19 Sophie Musset , Nicole Vilmer , Véronique Bommier

Flare emissions in X-ray and EUV wavelengths have previously been modeled as the plasma response to impulsive heating from magnetic reconnection. Some flares exhibit gradually evolving X-ray and EUV light curves, which are believed to…

Solar and Stellar Astrophysics · Physics 2016-04-20 Jiong Qiu , Dana W. Longcope

Magnetic reconnection is a fundamental physical process in various astrophysical, space, and laboratory environments. Many pieces of evidence for magnetic reconnection have been uncovered. However, its specific processes that could be…

Solar and Stellar Astrophysics · Physics 2018-10-24 X. Cheng , Y. Li , L. F. Wan , M. D. Ding , P. F. Chen , J. Zhang , J. J. Liu

We present the analysis and interpretation of an observation of the flare star AD Leo (dM3e) with Chandra/LETG. The high resolution X-ray spectrum allowed us to infer the plasma emission measure distribution (EMD) vs. temperature, and the…

Astrophysics · Physics 2012-08-27 A. Maggio , J. J. Drake , V. Kashyap , F. R. Harnden, , G. Micela , G. Peres , S. Sciortino

The EUV late phase is the second increase of the irradiance of the warm coronal lines during solar flares, and has a crucial impact on the Earth's ionosphere. In this paper, we report on the extremely energetic EUV late phase of a pair of…

Solar and Stellar Astrophysics · Physics 2025-12-10 Ya Wang , Sargam M. Mulay , Lyndsay Fletcher

We report SDO/AIA observations of an extraordinary global extreme ultraviolet (EUV) wave triggered by the X8.2+ flare-CME eruption on 2017 September 10. This was one of the best EUV waves ever observed with modern instruments, yet it was…

Solar and Stellar Astrophysics · Physics 2018-09-19 Wei Liu , Meng Jin , Cooper Downs , Leon Ofman , Mark C. M. Cheung , Nariaki V. Nitta

Previous estimates of the solar flare abundances of Si, S, Cl, Ar, and K from the RESIK X-ray crystal spectrometer on board the CORONAS-F spacecraft were made on the assumption of isothermal X-ray emission. We investigate the effect on…

Solar and Stellar Astrophysics · Physics 2015-06-19 B. Sylwester , J. Sylwester , K. J. H. Phillips , A. Kepa , T. Mrosek

In this paper, we present a multi-wavelength analysis of two X-class solar eruptive flares of classes X2.2 and X9.3 that occurred in the sigmoidal active region NOAA 12673 on 2017 September 6, by combining observations of Atmospheric…

Solar and Stellar Astrophysics · Physics 2018-12-26 Prabir K. Mitra , Bhuwan Joshi , Avijeet Prasad , Astrid M. Veronig , R. Bhattacharyya

The objectives of the present study is to provide a better physical understanding of the complex inter-relation and evolution of several solar coronal features comprising a double-peak flare, a coronal dimming caused by a CME, a CME-driven…

Solar and Stellar Astrophysics · Physics 2015-06-23 M. S. Madjarska , J. G. Doyle , J. Shetye

We report striking Doppler velocity gradients observed during the well-observed September 10th 2017 solar flare, and argue that they are consistent with the presence of an above-the-looptop termination shock beneath the flare current sheet.…

Solar and Stellar Astrophysics · Physics 2024-02-08 Ryan J. French , Sijie Yu , Bin Chen , Chengcai Shen , Sarah A. Matthews