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We detect rapid downflows of 150-217 km/s in IRIS Si IV 1402.77 nm measurements of an X9-class solar flare on 2024 October 3rd. The fast redshift values persist for over 15 minutes from flare onset, and can be split into two distinct stages…

Local helioseismology provides a unique opportunity to investigate the subsurface structure and dynamics of active regions and their effect on the large-scale flows and global circulation of the Sun. We use measurements of plasma flows in…

Solar and Stellar Astrophysics · Physics 2016-07-19 Alexander G. Kosovichev , Junwei Zhao , Stathis Ilonidis

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 study the acoustic properties of the solar chromosphere in the high-frequency regime using a time sequence of velocity measurements in the chromospheric Ca II 854.2 nm line taken with the Interferometric Bidimensional Spectrometer…

Astrophysics · Physics 2010-11-11 K. P. Reardon , F. Lepreti , V. Carbone , A. Vecchio

The Extreme ultraviolet Imaging Spectrometer (EIS) on board Hinode is the first solar telescope to obtain wide slit spectral images that can be used for detecting Doppler flows in transition region and coronal lines on the Sun and to relate…

Astrophysics · Physics 2009-11-13 D. E. Innes , R. Attie , H. Hara , M. S. Madjarska

Despite being the most prominent emission line in the solar spectrum, there has been a notable lack of studies devoted to variations in Ly$\alpha$ emission during solar flares in recent years. However, the few examples that do exist have…

Solar and Stellar Astrophysics · Physics 2016-03-02 Ryan O. Milligan , Phillip C. Chamberlin

We report three-minute oscillations in the solar chromosphere driven by a strong downflow event in a sunspot. We used the Fast Imaging Solar Spectrograph of the 1.6 m New Solar Telescope and the Interface Region Imaging Spectrograph (IRIS).…

Solar and Stellar Astrophysics · Physics 2016-04-27 Hannah Kwak , Jongchul Chae , Donguk Song , Yeon-Han Kim , Eun-Kyung Lim , Maria S. Madjarska

Solar filaments exist as stable structures for extended periods of time before many of them form the core of a CME. We examine the properties of an erupting filament on 2017 May 29--30 with high-resolution He I 10830 A and Halpha spectra…

In this paper, we present the observations of two successive fast-mode extreme ultraviolet (EUV) wave events observed on 2016 July 23. Both fast-mode waves were observed by the Atmospheric Imaging Assembly (AIA) instrument on board the…

Solar and Stellar Astrophysics · Physics 2018-08-22 R. Chandra , P. F. Chen , R. Joshi , B. Joshi , B. Schmieder

High-frequency wave phenomena present a great deal of interest as one of the possible candidates to contribute to the energy input required to heat the corona as a part of the AC heating theory. However, the resolution of imaging…

Solar and Stellar Astrophysics · Physics 2023-04-05 Elena Petrova , Norbert Magyar , Tom Van Doorsselaere , David Berghmans

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

IRIS data allow us to study the solar transition region (TR) with an unprecedented spatial resolution of 0.33 arcsec. On 2013 August 30, we observed bursts of high Doppler shifts suggesting strong supersonic downflows of up to 200 km/s and…

In this Letter we present a seismological detection of a rising motion of magnetic flux in the shallow convection zone of the Sun, and show estimates of the emerging speed and its decelerating nature. In order to evaluate the speed of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Shin Toriumi , Stathis Ilonidis , Takashi Sekii , Takaaki Yokoyama

Spatially-resolved X-ray observations are the key to understanding electron acceleration in solar flares. Currently, the underlying processes that efficiently energize solar flare particles are poorly constrained. Abundant flare…

Solar and Stellar Astrophysics · Physics 2026-03-09 Morgan Stores , Natasha Jeffrey , Ewan Dickson , James McLaughlin , Eduard Kontar

High-speed downflows have been observed in the solar transition region (TR) and lower corona for many decades. Despite their abundance, it has been hard to find signatures of such downflows in the solar chromosphere. In this work, we target…

Solar and Stellar Astrophysics · Physics 2021-03-24 Souvik Bose , Jayant Joshi , Vasco M. J. Henriques , Luc Rouppe van der Voort

Solar active regions (ARs) that produce major flares typically exhibit strong plasma shear flows around photospheric magnetic polarity inversion lines (MPILs). It is therefore important to quantitatively measure such photospheric shear…

Solar and Stellar Astrophysics · Physics 2018-10-29 Sung-Hong Park , Jordan A. Guerra , Peter T. Gallagher , Manolis K. Georgoulis , D. Shaun Bloomfield

A proxy for horizontal electric currents in the solar photosphere was suggested. For a set of evolving active regions (ARs) observed with {\it Solar and Heliospheric Observatory (SOHO)} Michelson Doppler Imager (MDI) in the high resolution…

Astrophysics · Physics 2008-06-11 Valentyna Abramenko

We firstly present the Solar Dynamics Observatory observations of four homologous flux ropes in active region (AR) 11745 on 2013 May 20-22. The four flux ropes are all above the neutral line of the AR, with endpoints anchoring at the same…

Solar and Stellar Astrophysics · Physics 2015-06-17 Ting Li , Jun Zhang

Solar flares are efficient particle accelerators with a large fraction of released magnetic energy (10-50%) converted into energetic particles such as hard X-ray producing electrons. This energy transfer process is not well constrained,…

Solar and Stellar Astrophysics · Physics 2023-04-12 Morgan Stores , Natasha L. S. Jeffrey , James A. McLaughlin

Outflows of plasma at the edges of active regions surrounded by quiet Sun are now a common observation with the Hinode satellite. While there is observational evidence to suggest that the outflows are originating in the magnetic field…

Solar and Stellar Astrophysics · Physics 2015-05-14 M. J. Murray , D. Baker , L. van Driel-Gesztelyi , J. Sun