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We investigate the relationship between the blue shifts of a hot emission line and the nonthermal emissions in microwave and hard X-ray (HXR) wavelengths during the precursor of a solar flare on 2014 October 27. The flare precursor is…

Solar and Stellar Astrophysics · Physics 2018-02-21 Dong Li , Ying Li , Wei Su , Yu Huang , Zongjun Ning

We have carried out the first comprehensive investigation of enhanced line emission from molecular hydrogen, H$_{2}$ at 1333.79 {\AA}, observed at flare ribbons in SOL2014-04-18T13:03. The cool H$_{2}$ emission is known to be fluorescently…

Solar and Stellar Astrophysics · Physics 2021-02-24 Sargam M. Mulay , Lyndsay Fletcher

Flare kernels are compact features located in the solar chromosphere that are the sites of rapid heating and plasma upflow during the rise phase of flares. An example is presented from a M1.1 class flare observed on 2011 February 16 07:44…

Solar and Stellar Astrophysics · Physics 2015-06-12 Peter Young , George Doschek , Harry Warren , Hiro Hara

Solar flares result in an increase of the solar irradiance at all wavelengths. While the distribution of the flare fluence observed in coronal emission has been widely studied and found to scale as f(E) ~ E^{-\alpha}, with \alpha slightly…

Solar and Stellar Astrophysics · Physics 2015-10-08 M. Kretzschmar

During solar flares, a considerable portion of the flare atmosphere becomes heated; however, the energy deposition process is still unclear, especially in the lower solar atmosphere. Here, we present spectroscopic and imaging observations…

Solar and Stellar Astrophysics · Physics 2026-03-24 Girjesh Gupta , Ananya Rawat , Helen Mason , Robertus Erdélyi

Upflows at the edges of active regions (ARs) are studied by spatially and temporally combining multi-instrument observations obtained with EIS/Hinode, AIA and HMI/SDO and IBIS/NSO, to derive their plasma parameters. This information is used…

Solar and Stellar Astrophysics · Physics 2015-11-18 K. Vanninathan , M. S. Madjarska , K. Galsgaard , Z. Huang , J. G. Doyle

We report the first observation of multiple-periodic propagating disturbances along a fan-like coronal structure simultaneously detected in both intensity and Doppler shift in the Fe XII 195 A line with the EUV Imaging Spectrometer (EIS)…

Solar and Stellar Astrophysics · Physics 2010-11-11 T. J. Wang , L. Ofman , J. M. Davila , J. T. Mariska

We exploit the high spatial resolution and high cadence of the Interface Region Imaging Spectrograph (IRIS) to investigate the response of the transition region and chromosphere to energy deposition during a small flare. Simultaneous…

Solar and Stellar Astrophysics · Physics 2016-09-28 Harry P. Warren , Jeffrey W. Reep , Nicholas A. Crump , Paulo J. A. Simoes

We present the first Hinode/EIS observations of 5 min quasi-periodic oscillations detected in a transition-region line (He II) and five coronal lines (Fe X, Fe XII, Fe XIII, Fe XIV, and Fe XV) at the footpoint of a coronal loop. The…

Solar and Stellar Astrophysics · Physics 2010-11-11 T. J. Wang , L. Ofman , J. M. Davila

We present different signatures of chromospheric evaporation in two solar flares observed by the Interface Region Imaging Spectrograph (IRIS). In the B1.6 flare on 2016 December 6 (SOL2016-12-06T10:40), the transition region Si IV line and…

Solar and Stellar Astrophysics · Physics 2019-07-10 Y. Li , M. D. Ding , J. Hong , H. Li , W. Q. Gan

We have previously found a temperature-dependent upflow in the dimming region following a coronal mass ejection (CME) observed by the {\it Hinode} EUV Imaging Spectrometer (EIS). In this paper, we reanalyzed the observations along with…

Solar and Stellar Astrophysics · Physics 2015-05-30 S. Imada , H. Hara , T. Watanabe , I. Murakami , L. K. Harra , T. Shimizu , E. G. Zweibel

Context. Magnetic reconnection during flares takes place in the corona but a substantial part of flare energy is deposited in the chromosphere. However, high-resolution spectro-polarimetric chromospheric observations of flares are very…

Solar and Stellar Astrophysics · Physics 2019-01-09 Tine Libbrecht , Jaime de la Cruz Rodriguez , Sanja Danilovic , Jorrit Leenaarts , Hiva Pazira

We present plasma diagnostics of an EIT wave observed with high cadence in Hinode/EIS sit-and-stare spectroscopy and SDO/AIA imagery obtained during the HOP-180 observing campaign on 2011 February 16. At the propagating EIT wave front, we…

Solar and Stellar Astrophysics · Physics 2015-06-03 A. M. Veronig , P. Gomory , I. W. Kienreich , N. Muhr , B. Vrsnak , M. Temmer , H. P. Warren

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…

The temperature distribution of the emitting plasma is a crucial constraint when studying the heating of solar flare footpoints. However, determining this for impulsive phase footpoints has been difficult in the past due to insufficient…

Solar and Stellar Astrophysics · Physics 2015-06-15 D. R. Graham , I. G. Hannah , L. Fletcher , R. O. Milligan

In a solar flare, a large fraction of the magnetic energy released is converted rapidly to the kinetic energy of non-thermal particles and bulk plasma motion. This will likely result in non-equilibrium particle distributions and turbulent…

Solar and Stellar Astrophysics · Physics 2017-02-15 Natasha L. S. Jeffrey , Lyndsay Fletcher , Nicolas Labrosse

We present a detailed investigation of the Doppler shift oscillations in a hot loop during an M7.1 flare on 2014 October 27 observed by the Interface Region Imaging Spectrograph. The periodic oscillations are observed in the Doppler shift…

Solar and Stellar Astrophysics · Physics 2017-11-15 Dong Li , Zongjun Ning , Yu Huang , N. -H. Chen , Qingmin Zhang , Yingna Su , Wei Su

Here we present the study of a compact emission source during an X1.3 flare on 2022-March-30. Within a $\sim41$~s period (17:34:48 UT to 17:35:29 UT), IRIS observations show spectral lines of Mg II, C II and Si IV with extremely broadened,…

Solar and Stellar Astrophysics · Physics 2023-09-13 Yan Xu , Graham S. Kerr , Vanessa Polito , Nengyi Huang , Ju Jing , Haimin Wang

Magnetic energy released in the corona by solar flares reaches the chromosphere where it drives characteristic upflows and downflows known as evaporation and condensation. These flows are studied here for the case where energy is…

Solar and Stellar Astrophysics · Physics 2015-06-22 D. W. Longcope

We present new measurements of the time variability of intensity, Doppler and non-thermal velocities in moss in an active region core observed by the EUV Imaging Spectrometer on Hinode in 2007, June. The measurements are derived from…

Solar and Stellar Astrophysics · Physics 2009-09-28 David H. Brooks , Harry P. Warren