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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…

We investigate numerically the time evolution of velocity and magnetic field fluctuations in a coronal loop, focusing on the dynamics due to both phase mixing and turbulent cascade. The intensity, doppler velocity and non-thermal broadening…

Employing high-resolution EUV imaging observations from SDO/AIA, we analyse a compressive plasma oscillation in a hot coronal loop triggered by a C-class flare near one of its foot points as first studied by Kumar et al. We investigate the…

Solar and Stellar Astrophysics · Physics 2021-06-30 S. Krishna Prasad , T. Van Doorsselaere

We present SDO/AIA observations of an eruptive X-class flare of July 12, 2012, and compare its evolution with the predictions of a 3D numerical simulation. We focus on the dynamics of flare loops that are seen to undergo slipping…

Solar and Stellar Astrophysics · Physics 2015-06-18 Jaroslav Dudík , Miho Janvier , Guillaume Aulanier , Giulio Del Zanna , Marian Karlický , Helen Mason , Brigitte Schmieder

We present the analyses of intense X-ray flares detected on the active fast rotator AB Dor using observations from the XMM-Newton. A total of 21 flares are detected, and 13 flares are analysed in detail. The total X-ray energy of these…

Solar and Stellar Astrophysics · Physics 2023-10-23 Shweta Didel , Jeewan C. Pandey , A. K. Srivastava , Gurpreet Singh

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

We have analyzed H-alpha intensity images obtained at a 1 minute cadence with the Global Oscillation Network Group (GONG) system to investigate the properties of oscillations in the 0-8 mHz frequency band at the location and time of strong…

Solar and Stellar Astrophysics · Physics 2018-03-08 Teresa Monsue , Frank Hill , Keivan G. Stassun

Using data from observations made with XMM-Newton, we present an X-ray analysis of two flares observed in $\xi$ Boo. The flare loop parameters are derived using various loop models including state-of-the-art hydrodynamic flare model. The…

Solar and Stellar Astrophysics · Physics 2017-08-02 J. C. Pandey , A. K. Srivastava

We investigate observational signatures of explosive chromospheric evaporation during a white-light flare (WLF) that occurred on 2022 August 27. Using the moment analysis, bisector techniques, and the Gaussian fitting method, red-shifted…

Solar and Stellar Astrophysics · Physics 2023-06-29 Dong Li , Chuan Li , Ye Qiu , Shihao Rao , Alexander Warmuth , Frederic Schuller , Haisheng Zhao , Fanpeng Shi , Jun Xu , Zongjun Ning

Quasi-periodic intensity disturbances propagating upward along the coronal structure have been extensively studied using EUV imaging observations from SOHO/EIT and TRACE. They were interpreted as either slow mode magnetoacoustic waves or…

Solar and Stellar Astrophysics · Physics 2012-01-26 Tongjiang Wang , Leon Ofman , Joseph M. Davila

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

In this paper, we analyze the high-resolution UV spectra for a C1.7 solar flare (SOL2017-09-09T06:51) observed by the \textit{Interface Region Imaging Spectrograph} (\textit{IRIS}). {We focus on the spectroscopic observations at the…

Solar and Stellar Astrophysics · Physics 2020-12-02 Yi-An Zhou , Y. Li , M. D. Ding , Jie Hong , Ke Yu

We report on the physical properties of small-scale transient flows observed simultaneously at high cadence with the SUMER spectrometer and the TRACE imager in the plage area of an active region. Our major objective is to provide a better…

Astrophysics · Physics 2009-11-13 M. S. Madjarska , J. G. Doyle

Solar flares form and release energy across a large number of magnetic loops. The global parameters of flares, such as the total energy released, duration, physical size, etc., are routinely measured, and the hydrodynamics of a coronal loop…

Solar and Stellar Astrophysics · Physics 2018-04-18 Jeffrey W. Reep , Vanessa Polito , Harry P. Warren , Nicholas A. Crump

The Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft observed flare footpoint regions coincident with a surge for a M3.7 flare observed on 25 September 2011 at N12 E33 in active region 11302. The flare was observed in…

Solar and Stellar Astrophysics · Physics 2015-10-30 George A. Doschek , Harry P. Warren , Brian R. Dennis , Jeffrey W. Reep , Amir Caspi

The study examines the heating profile of hot solar transition region loops, particularly focusing on transient brightenings observed in IRIS 1400{\AA} slit-jaw images. The findings challenge the adequacy of simplistic, singular heating…

Solar and Stellar Astrophysics · Physics 2024-05-15 Shah Mohammad Bahauddin , Stephen J Bradshaw

We report the observations of a flux rope at transition region temperatures with the \emph{Interface Region Imaging Spectrograph} (IRIS) on 30 August 2014. Initially, magnetic flux cancellation constantly took place and a filament was…

Solar and Stellar Astrophysics · Physics 2015-11-04 Ting Li , Jun Zhang

Context: Flare kernels brighten simultaneously in all SDO/AIA channels making it difficult to determine their temperature structure. IRIS is able to spectrally resolve Fe xxi emission from cold chromospheric brightenings, so can be used to…

Solar and Stellar Astrophysics · Physics 2016-02-17 D. Li , D. E. Innes , Z. J. Ning

Extreme ultraviolet imaging spectroscopic observations often show an increase in line width around the loop-top or above-loop-top (ALT) region of solar flares, suggestive of turbulence. In addition, recent spectroscopic observations found…

Solar and Stellar Astrophysics · Physics 2023-02-08 Kengo Shibata , Shinsuke Takasao , Katharine K. Reeves

Diffuse far-ultraviolet (FUV) emissions from the Lupus Loop region (SNR 330.0+15.0) have been observed with Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR), also known as Far-ultraviolet IMaging Spectrograph (FIMS). We…

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