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Coronal upflows at the edges of active regions (AR), which are a possible source of slow solar wind, have been found to connect with dynamics in the transition region. To infer at what scale transition region dynamics connect to AR upflows,…

Solar and Stellar Astrophysics · Physics 2021-09-08 Zhenghua Huang , Lidong Xia , Hui Fu , Zhenyong Hou , Ziyuan Wang

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

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

Active regions are thought to be one contributor to the slow solar wind. Upflows in EUV coronal spectral lines are routinely osberved at their boundaries, and provide the most direct way for upflowing material to escape into the…

Solar and Stellar Astrophysics · Physics 2021-08-18 David H. Brooks , Louise Harra , Stuart D. Bale , Krzysztof Barczynski , Cristina Mandrini , Vanessa Polito , Harry P. Warren

Perhaps the most compelling evidence for the role of magnetic reconnection in solar flares comes from the supra-arcade downflows that have been observed above many post-flare loop arcades. These downflows are thought to be related to highly…

Solar and Stellar Astrophysics · Physics 2015-05-30 Harry P. Warren , Casey M. O'Brien , Neil R. Sheeley

Active region (AR) outflows have been studied in detail since the launch of \textit{Hinode}/EIS and are believed to provide a possible source of mass and energy to the slow solar wind. In this work, we investigate the lower atmospheric…

Solar and Stellar Astrophysics · Physics 2020-11-11 Vanessa Polito , Bart De Pontieu , Paola Testa , David H. Brooks , Viggo Hansteen

We investigate various dynamic processes including magnetic reconnection, chromospheric evaporation, and coronal rain draining in two limb solar flares through imaging and spectroscopic observations from the Interface Region Imaging…

Solar and Stellar Astrophysics · Physics 2022-08-17 Ke Yu , Y. Li , Jie Hong , De-Chao Song , M. D. Ding

We report a spectroscopic analysis of an EIT wave event that occurred in active region 11081 on 2010 June 12 and was associated with an M2.0 class flare. The wave propagated near circularly. The south-eastern part of the wave front passed…

Solar and Stellar Astrophysics · Physics 2015-05-28 F. Chen , M. D. Ding , P. F. Chen , L. K. Harra

We study the plasma flows in the solar photosphere during the emergence of two small active regions, NOAA 9021 and 10768. Using SOHO/MDI data, we find that the strong plasma upflows appear at the initial stage of active region formation,…

Solar and Stellar Astrophysics · Physics 2017-05-01 Anna Khlystova , Shin Toriumi

Since the discovery of quasi-periodic propagating oscillations with periods of order three to ten minutes in coronal loops with TRACE and EIT (later with EUVI and EIS), they have been almost universally interpreted as evidence for…

Solar and Stellar Astrophysics · Physics 2015-05-19 Bart De Pontieu , Scott W. McIntosh

The chromosphere above active regions (ARs) on the Sun hosts magnetized supersonic downflows. Studies of these supersonic downflows help to decipher the magnetic fine structure and dynamics of the chromosphere. We perform a statistical…

Solar and Stellar Astrophysics · Physics 2022-07-26 K. Sowmya , A. Lagg , S. K. Solanki , J. S. Castellanos Durán

Recent EUV spectroscopic observations indicate that slow magnetosonic waves are present in active region (AR) loops. Some of the spectral data were also interpreted as evidence of fast (~100-300 km/s) quasi-periodic flows. We have performed…

Solar and Stellar Astrophysics · Physics 2015-06-05 Leon Ofman , Tongjiang Wang , Joseph M. Davila

Magnetic reconnection is believed to be the dominant energy release mechanism in solar flares. The standard flare model predicts both downward and upward outflow plasmas with speeds close to the coronal Alfv\'{e}n speed. Yet, spectroscopic…

Solar and Stellar Astrophysics · Physics 2014-12-02 Hui Tian , Gang Li , Katharine K. Reeves , John C. Raymond , Fan Guo , Wei Liu , Bin Chen , Nicholas A. Murphy

We have shown previously that SOHO/UVCS data allow us to detect active region (AR) outflows at coronal altitudes higher than those reached by other instrumentation. These outflows are thought to be a component of the slow solar wind. Our…

Solar and Stellar Astrophysics · Physics 2016-10-07 L. Zangrilli , G. Poletto

Three homologous C-class flares and one last M-class flare were observed by both the Solar Dynamics Observatory (SDO) and the Hinode EUV Imaging Spectrometer (EIS) in the AR 11429 on March 9, 2012. All the recurrent flares occurred within a…

Solar and Stellar Astrophysics · Physics 2017-04-26 V. Polito , G. Del Zanna , G. Valori , E. Pariat , H. E. Mason , J. Dudik , M. Janvier

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

Context. Observations of many active regions show a slow systematic outflow/upflow from their edges lasting from hours to days. At present no physical explanation has been proven, while several suggestions have been put forward. Aims. This…

Solar and Stellar Astrophysics · Physics 2021-08-25 K. Galsgaard , M. S. Madjarska , K. Vanninathan , Z. Huang , M. Presmann

Recent observations from Parker Solar Probe have revealed that the solar wind has a highly variable structure. How this complex behaviour is formed in the solar corona is not yet known, since it requires omnipresent fluctuations, which…

With the SDO/AIA instrument, continuous and intermittent plasma outflows are observed on the boundaries of an active region along two distinct open coronal loops. %with the speed of 30$\sim$200 km s$^{-1}$. By investigating the temporal…

Solar and Stellar Astrophysics · Physics 2014-05-16 S. Liu , J. T. Su

Solar flares are widely accepted to be powered by magnetic reconnection that involves complex dynamics in various scales. The flare supra-arcade and loop-top region, directly impacted by fast reconnection downflows, contains a wealth of…

Solar and Stellar Astrophysics · Physics 2025-05-27 Tingyu Gou , Katharine K. Reeves