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Investigations of the dynamics of the hot coronal plasma are crucial for understanding various space weather phenomena and making in-depth analyzes of the global heating of the solar corona. We present here numerical simulations of…

Solar and Stellar Astrophysics · Physics 2021-09-01 Malherbe Jean-Marie , Mein Pierre , Sayede Frederic , Rudawy Pawel , Phillips Kenneth , Keenan Francis , Rybak Jan

It is well-known that extreme ultraviolet emission emitted at the solar surface is absorbed by overlying cool plasma. Especially in active regions dark lanes in EUV images suggest that much of the surface activity is obscured. Simultaneous…

Solar and Stellar Astrophysics · Physics 2016-12-14 N. -H. Chen , D. E. Innes

We report on the first Interface Region Imaging Spectrograph (IRIS) study of cool transition region loops. This class of loops has received little attention in the literature. A cluster of such loops was observed on the solar disk in active…

Solar and Stellar Astrophysics · Physics 2015-09-09 Zhenghua Huang , Lidong Xia , Bo Li , Maria S. Madjarska

The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, and corona with 0.33-0.4 arcsec spatial resolution, 2 s temporal…

A significant impediment to solving the coronal heating problem is that we currently only observe active region (AR) loops in their cooling phase. Previous studies showed that the evolution of cooling loop densities and apex temperatures…

Solar and Stellar Astrophysics · Physics 2024-01-10 David H. Brooks , Jeffrey W. Reep , Ignacio Ugarte-Urra , John E. Unverferth , Harry P. Warren

A blowout jet occurred within the south coronal hole on 9 February 2011 at 09:00 UT and was observed by the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory, and the EUV…

Solar and Stellar Astrophysics · Physics 2015-06-17 Peter Young , Karin Muglach

Using the observations recorded by Atmospheric Imaging Assembly (AIA) on-board the Solar Dynamics Observatory (SDO), the Interface Region Imaging Spectrograph (IRIS) and the Extreme-ultraviolet Imaging Spectrometer (EIS) and X-Ray Telescope…

Solar and Stellar Astrophysics · Physics 2018-05-07 G. R. Gupta , Aveek Sarkar , Durgesh Tripathi

We present direct evidence for the detection of the main energy release site in a non-eruptive solar flare, SOL2013-11-09T06:38UT. This GOES C2.7 event was characterised by two flaring ribbons and a compact, bright coronal source located…

Solar and Stellar Astrophysics · Physics 2015-05-06 Paulo J. A. Simões , David R. Graham , Lyndsay Fletcher

Spectral line widths are often observed to be larger than can be accounted for by thermal and instrumental broadening alone. This excess broadening is a key observational constraint for both nanoflare and wave dissipation models of coronal…

Solar and Stellar Astrophysics · Physics 2016-03-23 David H. Brooks , Harry P. Warren

A complete understanding of Doppler shift in active region loops can help probe the basic physical mechanism involved into the heating of those loops. Here we present observations of upflows in coronal loops detected in a range of…

Solar and Stellar Astrophysics · Physics 2015-06-05 Durgesh Tripathi , Helen Mason , Giulio Del Zanna , Steven Bradshaw

We analyze a solar active region observed by the Hinode CaII H line using the time-distance helioseismology technique, and infer wave-speed perturbation structures and flow fields beneath the active region with a high spatial resolution.…

Solar and Stellar Astrophysics · Physics 2014-11-20 Junwei Zhao , Alexander G. Kosovichev , Takashi Sekii

Observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) reveal ubiquitous episodic outflows (jets) with an average speed around 120 km s-1 at temperatures often exceeding a million degree in…

Solar and Stellar Astrophysics · Physics 2011-07-27 Hui Tian , Scott W. McIntosh , Shadia Rifal Habbal , Jiansen He

High-resolution observations of dynamic phenomena give insight into properties and processes that govern the low solar atmosphere. We present the analysis of jet-like phenomena emanating from a penumbral foot-point in active region (AR)…

Solar and Stellar Astrophysics · Physics 2020-10-09 Llŷr Dafydd Humphries , Erwin Verwichte , David Kuridze , Huw Morgan

New instrumental and telescopes covering the optical and ultra-violet spectral regions have revealed a range of small-scale dynamic features, many which may be related. For example, the range of spicule-like features hints towards a…

Solar and Stellar Astrophysics · Physics 2023-08-02 Nived Vilangot Nhalil , Juie Shetye , J. Gerry Doyle

Since their discovery twenty year ago, transition region bright points (TRBPs) have never been observed spectroscopically. Bright point properties have not been compared with similar transition region and coronal structures. In this work we…

Wave theories of heating the chromosphere, corona, and solar wind due to photospheric fluctuations are strengthened by the existence of observed wave coherency up to the transition region (TR). The coherency of solar spicules' intensity…

Solar and Stellar Astrophysics · Physics 2017-02-08 Alireza Ahangarzadeh Maralani , Ehsan Tavabi , Ali Ajabshirizadeh

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

Wide-field EUV telescopes imaging in spectral bands sensitive to 1 MK plasma on the Sun often observe extended ray-like coronal structures stretching radially from active regions to distances of 1.5-2Rsun, which represent the EUV…

Solar and Stellar Astrophysics · Physics 2014-01-24 F. Goryaev , V. Slemzin , L. Vainshtein , D. R. Williams

Based on observations from the EUV Imaging Spectrometer (EIS) on board Hinode, the existence of a broad distribution of blue and red Dopplershift in active region loops has been revealed; the distribution of Dopplershifts depends on the…

Solar and Stellar Astrophysics · Physics 2017-06-07 S. Regnier , R. W. Walsh

We analyze and model an M1.0 flare observed by SDO/AIA and Hinode/EIS to investigate how flare loops are heated and evolve subsequently. The flare is composed of two distinctive loop systems observed in EUV images. The UV 1600 \AA emission…

Solar and Stellar Astrophysics · Physics 2015-06-11 Y. Li , J. Qiu , M. D. Ding
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