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We present observations of transient active region heating events observed with the Extreme Ultraviolet Imaging Spectrometer (EIS) and X-ray Telescope (XRT) on Hinode. This initial investigation focuses on NOAA active region 10940 as…

Combined tearing-thermal evolution plays an important role in the disruption of current sheets, and formation of cool condensations within the solar atmosphere. However, this has received limited attention to date. We numerically explore a…

Solar and Stellar Astrophysics · Physics 2023-10-18 Samrat Sen , Jack Jenkins , Rony Keppens

In this paper, we discuss the temperature distribution and evolution of a microflare, simultaneously observed by Hinode XRT, EIS, and SDO AIA. We find using EIS lines that during peak emission the distribution is nearly isothermal and…

Solar and Stellar Astrophysics · Physics 2019-08-21 Urmila Mitra-Kraev , Giulio Del Zanna

The presence of current sheet instabilities, such as the tearing mode instability, are needed to account for the observed rate of energy release in solar flares. Insights into these current sheet dynamics can be revealed by the behaviour of…

Solar and Stellar Astrophysics · Physics 2021-12-08 Ryan J. French , Sarah A. Matthews , I. Jonathan Rae , Andrew W. Smith

Images of an east-limb flare on 3 November 2010 taken in the 131 \AA\ channel of the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory provide a convincing example of a long current sheet below an erupting plasmoid, as…

Solar and Stellar Astrophysics · Physics 2015-06-16 Pankaj Kumar , D. E. Innes

We investigate the August 9, 2011 solar flare of X-ray class X6.9, the "hottest" flare from 2000 to 2012, with a peak plasma temperature according to GOES data of 32.5 MK. Our goal is to determine the cause of such an anomalously high…

Solar and Stellar Astrophysics · Physics 2015-06-23 I. N. Sharykin , A. B. Struminsky , I. V. Zimovets

The chromospheric response to the input of flare energy is marked by extended extreme ultraviolet (EUV) ribbons and hard X-ray (HXR) footpoints. These are usually explained as the result of heating and bremsstrahlung emission from…

Solar and Stellar Astrophysics · Physics 2016-01-20 Paulo J. A. Simões , David R. Graham , Lyndsay Fletcher

In this article, we measure the mean magnetic shear from the morphological evolution of flare ribbons, and examine the evolution of flare thermal and non-thermal X-ray emissions during the progress of flare reconnection. We analyze three…

Solar and Stellar Astrophysics · Physics 2022-07-20 Jiong Qiu , Jianxia Cheng

We studied a circular-ribbon flare, SOL2014-12-17T04:51, with emphasis on its thermal evolution as determined by the Differential Emission Measure (DEM) inversion analysis of the extreme ultraviolet (EUV) images of the Atmospheric Imaging…

Solar and Stellar Astrophysics · Physics 2020-08-13 Jeongwoo Lee , Judith T. Karpen , Chang Liu , Haimin Wang

We conduct a detailed analysis of an M1.3 limb flare occurring on 2017 July 3, which have the X-ray observations recorded by multiple hard X-ray telescopes, including Hard X-ray Modulation Telescope (Insight-HXMT), Ramaty High Energy Solar…

High Energy Astrophysical Phenomena · Physics 2022-05-04 Ping Zhang , Wei Wang , Yang Su , Shuangnan Zhang , Liming Song , Fangjun Lu , Shu Zhang

We perform Differential Emission Measure (DEM) analysis of an M7.7 flare that occurred on 2012 July 19 and was well observed by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamic Observatory. Using the observational data with…

Solar and Stellar Astrophysics · Physics 2015-06-19 J. Q. Sun , X. Cheng , M. D. Ding

Magnetic reconnection changes the magnetic field topology and powers explosive events in astrophysical, space and laboratory plasmas. For flares and coronal mass ejections (CMEs) in the solar atmosphere, the standard model predicts the…

Solar and Stellar Astrophysics · Physics 2010-10-11 Rui Liu , Jeongwoo Lee , Tongjiang Wang , Guillermo Stenborg , Chang Liu , Haimin Wang

We present the first observational study of the onset and evolution of solar flare turbulence in the lower solar atmosphere on an unprecedented time scale of 1.7 s using the Interface Region Imaging Spectrograph observing plasma at a…

Solar and Stellar Astrophysics · Physics 2018-12-27 N. L. S. Jeffrey , L. Fletcher , N. Labrosse , P. J. A. Simões

The Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft obtains high resolution spectra of the solar atmosphere in two wavelength ranges: 170 - 210 and 250 - 290 angstroms. These wavelength regions contain a wealth of…

Solar and Stellar Astrophysics · Physics 2014-11-18 Yuan-Kuen Ko , George A. Doschek , Harry P. Warren , Peter R. Young

Using one-arcsecond-slit scan observations from the Hinode/EUV Imaging Spectrometer (EIS) on 05 February 2007, we find the plasma outflows in the open and expanding coronal funnels at the eastern boundary of AR 10940. The Doppler velocity…

Solar and Stellar Astrophysics · Physics 2015-06-22 A. K. Srivastava , P. Konkol , K. Murawski , B. N. Dwivedi , A. Mohan

We present observations of high temperature emission in the core of a solar active region using instruments on Hinode and SDO. These multi-instrument observations allow us to determine the distribution of plasma temperatures and follow the…

Solar and Stellar Astrophysics · Physics 2015-05-20 Harry P. Warren , David H. Brooks , Amy R. Winebarger

The first simultaneous observations of the Fe XVIII 974.86 {\AA} and Fe XX 721.56 {\AA} forbidden lines from the Spectral Imaging of the Coronal Environment (SPICE) spectrograph on Solar Orbiter are presented. The lines were observed from…

Solar and Stellar Astrophysics · Physics 2025-05-02 Peter R. Young , Andrew R. Inglis , Graham S. Kerr , Therese A. Kucera , Daniel F. Ryan

It is widely believed that magnetic flux ropes are the key structure of solar eruptions; however, their observable counterparts are not clear yet. We study a flare associated with flux rope eruption in a comprehensive radiative…

Solar and Stellar Astrophysics · Physics 2022-07-20 Can Wang , Feng Chen , Mingde Ding , Zekun Lu

The present work is on the study of a coronal streamer observed in March 2008 at high spectral and spatial resolution by the Ultraviolet Coronagraph Spectrometer (UVCS) onboard SOHO. On the basis of a spectroscopic analysis of the O VI…

Solar and Stellar Astrophysics · Physics 2011-11-14 Lucia Abbo , Ester Antonucci , Roberto Lionello , Zoran Mikić , Pete Riley

We use RHESSI high-resolution imaging and spectroscopy observations from ~5 to 100 keV to characterize the hot thermal plasma during the 2002 July 23 X4.8 flare. These measurements of the steeply falling thermal X-ray continuum are well fit…

Solar and Stellar Astrophysics · Physics 2011-05-17 A. Caspi , R. P. Lin