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Related papers: Relationship between EUV microflares and small-sca…

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We study the association of solar flares with coronal mass ejections (CMEs) during the deep, extended solar minimum of 2007-2009, using extreme-ultraviolet (EUV) and white-light (coronagraph) images from the {\it Solar Terrestrial Relations…

Solar and Stellar Astrophysics · Physics 2015-06-16 N. V. Nitta , M. J. Aschwanden , S. L. Freeland , J. R. Lemen , J. -P. Wülser , D. M. Zarro

We have explored the magnetic flux evolution and temperature variation in a coronal-hole region, using Big Bear Solar Observatory (BBSO) deep magnetograms and {\it SOHO}/EIT images observed from 2005 October 10 to 14. For comparison, we…

Astrophysics · Physics 2010-11-11 Jun Zhang , Guiping Zhou , Jingxiu Wang , Haimin Wang

Recent observations suggest that magnetic flux cancellation may play a crucial role in heating the Sun's upper atmosphere (chromosphere, transition region, corona). Here, we intended to validate an analytic model for magnetic reconnection…

Solar and Stellar Astrophysics · Physics 2020-07-08 Sung-Hong Park

A wide variety of phenomena such as gentle but persistent brightening, dynamic slender features (~100 km), and compact (~1'') ultraviolet (UV) bursts are associated with the heating of the solar chromosphere. High spatio-temporal resolution…

Solar and Stellar Astrophysics · Physics 2018-10-03 H. N. Smitha , L. P. Chitta , T. Wiegelmann , S. K. Solanki

Coronal dimmings, localized regions of reduced emission in the EUV and soft X-rays, are interpreted as density depletions due to mass loss during the CME expansion. They contain crucial information on the early evolution of CMEs low in the…

Solar and Stellar Astrophysics · Physics 2018-08-29 Karin Dissauer , Astrid M. Veronig , Manuela Temmer , Tatiana Podladchikova , Kamalam Vanninathan

Many studies of the solar corona have shown that the observed X-ray luminosity is well correlated with the total unsigned magnetic flux. In this paper we present results from the extensive numerical modeling of active regions observed with…

Astrophysics · Physics 2016-08-30 Harry P. Warren , Amy R. Winebarger

Localised transient EUV brightenings, sometimes named `campfires', occur throughout the quiet-Sun. However, there are still many open questions about such events, in particular regarding their temperature range and dynamics. In this…

We analyze high cadence high resolution observations of a C3.2 flare obtained by AIA/SDO on August 1, 2010. The flare is a long duration event with soft X-ray and EUV radiation lasting for over four hours. Analysis suggests that magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-03 Jiong Qiu , Wen-Juan Liu , Dana W. Longcope

NuSTAR is a highly sensitive focusing hard X-ray (HXR) telescope and has observed several small microflares in its initial solar pointings. In this paper, we present the first joint observation of a microflare with NuSTAR and Hinode/XRT on…

Magnetic loops filled with hot plasma are the main building blocks of the solar corona. Usually they have lengths of the order of the barometric scale height in the corona that is 50 Mm. Previously it has been suggested that miniature…

Solar and Stellar Astrophysics · Physics 2017-03-15 Krzysztof Barczynski , Hardi Peter , Sabrina L. Savage

Magnetic reconnection is a rapid energy release process that is believed to be responsible for flares on the Sun and stars. Nevertheless, such flare-related reconnection is mostly detected to occur in the corona, while there have been few…

Solar and Stellar Astrophysics · Physics 2016-03-21 Jie Hong , M. D. Ding , Ying Li , Kai Yang , Xin Cheng , Feng Chen , Cheng Fang , Wenda Cao

Understanding the dynamics of the quiet solar corona is important for answering key questions including the coronal heating problem. Multiple studies have suggested small-scale magnetic reconnection events may play a crucial role. These…

Solar and Stellar Astrophysics · Physics 2023-06-07 Surajit Mondal , Bin Chen , Sijie Yu

Solar campfires are fine-scale heating events, recently observed by Extreme Ultraviolet Imager (EUI), onboard Solar Orbiter. Here we use EUI 174\AA\ images, together with EUV images from SDO/AIA, and line-of-sight magnetograms from SDO/HMI…

Solar and Stellar Astrophysics · Physics 2021-11-17 Navdeep K. Panesar , Sanjiv K. Tiwari , David Berghmans , Mark C. M. Cheung , Daniel Muller , Frederic Auchere , Andrei Zhukov

The explanation of the coronal heating problem potentially lies in the existence of nanoflares, numerous small-scale heating events occuring across the whole solar disk. In this paper, we present the first imaging spectroscopy X-ray…

Solar microflares are ubiquitous in the solar corona, yet their driving mechanisms remain a subject of ongoing debate. Using high-resolution coronal observations from the Solar Orbiter's Extreme Ultraviolet Imager (EUI), we identified about…

Solar and Stellar Astrophysics · Physics 2025-03-17 Qingmei Wang , Yi Bi , Hongfei Liang , Jiayan Yang , Liufan Gong

Magnetic energy is required to heat the corona, the outer atmosphere of the Sun, to millions of degrees. We study the nature of the magnetic energy source that is probably responsible for the brightening of coronal loops driven by…

Solar and Stellar Astrophysics · Physics 2018-07-25 L. P. Chitta , H. Peter , S. K. Solanki

Extreme Ultraviolet (EUV) waves have been found for about 15 years. However, significant controversy remains over their physical natures and origins. In this paper, we report an EUV wave that was accompanied by an X1.9 flare and a partial…

Solar and Stellar Astrophysics · Physics 2015-06-05 Yuandeng Shen , Yu Liu

On 2016 September 20, the Interface Region Imaging Spectrograph observed an active region during its earliest emerging phase for almost 7 hours. The Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory observed…

Solar and Stellar Astrophysics · Physics 2018-03-14 Hui Tian , Xiaoshuai Zhu , Hardi Peter , Jie Zhao , Tanmoy Samanta , Yajie Chen

Context. Accurate detections of frequent small-scale extreme ultraviolet (EUV) brightenings are essential to the investigation of the physical processes heating the corona. Aims. We detected small-scale brightenings, termed campfires, using…

Small-scale explosive events or microflares occur throughout the chromospheric network of the Sun. They are seen as sudden bursts of highly Doppler shifted spectral lines of ions formed at temperatures in the range 2x10^4 - 5x10^5 K. They…

Astrophysics · Physics 2015-06-24 D. E. Innes , G. Toth