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It is well established that elemental abundances vary in the solar atmosphere and that this variation is organized by first ionization potential (FIP). Previous studies have shown that in the solar corona low-FIP elements, such as Fe, Si,…

Solar and Stellar Astrophysics · Physics 2016-06-22 Harry P. Warren , David H. Brooks , George A. Doschek , Uri Feldman

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…

Plasma flow measurements in solar active region filaments are rare, particularly in the infrared and ultraviolet ranges that probe the chromosphere and transition region. In addition, previous studies generally focused on prominences and…

Solar and Stellar Astrophysics · Physics 2025-11-04 M. Murabito , V. Andretta , S. Parenti , C. Kuckein , S. J. Gonzàlez Manrique , S. M. Lezzi , S. L. Guglielmino

To adequately constrain the frequency of energy deposition in active region cores in the solar corona, systematic comparisons between detailed models and observational data are needed. In this paper, we describe a pipeline for forward…

Solar and Stellar Astrophysics · Physics 2019-07-31 W. T. Barnes , S. J. Bradshaw , N. M. Viall

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

Solar coronal plasma composition is typically characterized by first ionization potential (FIP) bias. Using spectra obtained by Hinode's EUV Imaging Spectrometer (EIS) instrument, we present a series of large-scale, spatially resolved…

Solar and Stellar Astrophysics · Physics 2015-06-23 D. Baker , D. H. Brooks , P. Démoulin , S. L. Yardley , L. van Driel-Gesztelyi , D. M. Long , L. M. Green

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 present observations of high temperature emission in the core of a solar active region using instruments on Hinode and SDO. These multi-instrument observations allow us to determine the distribution of plasma temperatures and follow the…

Solar and Stellar Astrophysics · Physics 2015-05-20 Harry P. Warren , David H. Brooks , Amy R. Winebarger

Hinode's EUV Imaging Spectrometer (EIS) has discovered ubiquitous outflows of a few to 50 km/sec from active regions (ARs). These outflows are most prominent at the AR boundary and appear over monopolar magnetic areas. They are linked to…

Solar and Stellar Astrophysics · Physics 2014-11-20 D. Baker , L. van Driel-Gesztelyi , C. H. Mandrini , P. Demoulin , M. J. Murray

Solar active regions are associated with Evershed outflows in sunspot penumbrae, moat outflows surrounding sunspots, and extended inflows surrounding active regions. The latter have been identified on established active regions by various…

Solar and Stellar Astrophysics · Physics 2021-09-01 N. Gottschling , H. Schunker , A. C. Birch , B. Löptien , L. Gizon

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

The elemental composition of the Sun's hot atmosphere, the corona, shows a distinctive pattern that is different than the underlying surface, or photosphere (Pottasch 1963). Elements that are easy to ionize in the chromosphere are enhanced…

Solar and Stellar Astrophysics · Physics 2022-05-18 David H. Brooks , Deborah Baker , Lidia van Driel-Gesztelyi , Harry P. Warren , Stephanie L. Yardley

The composition of plasma in the solar corona is characterised by the First Ionisation Potential (FIP) bias, and is thought to be the result of a ponderomotive force acting in the chromosphere to separate ionised from neutral plasma.…

Solar and Stellar Astrophysics · Physics 2026-03-06 Éabha Power , David M. Long , Teodora Mihailescu , Laura A. Hayes

Spicules are the thin hair/grass-like structures that are prominently observed at the chromospheric solar limb. It is believed that fibrils and rapid blueshifted and redshifted excursions (RBEs and RREs; collectively referred to as REs)…

Solar and Stellar Astrophysics · Physics 2024-08-09 Ravi Chaurasiya , Ankala Raja Bayanna , R. E. Louis , T. M. D. Pereira , S. K. Mathew

In the corona, plasma is accelerated to hundreds of kilometers per second, and heated to temperatures hundreds of times hotter than the Sun's surface, before it escapes to form the solar wind. Decades of space-based experiments have shown…

One of the most important features in the solar atmosphere is magnetic network and its rela- tionship with the transition region (TR), and coronal brightness. It is important to understand how energy is transported into the corona and how…

Solar and Stellar Astrophysics · Physics 2018-03-21 Ehsan Tavabi

The small-scale moving intensity enhancements remotely observed in the extreme ultraviolet images of the solar active regions, which we refer to as active region moving campfires (ARMCs), are related to local plasma temperature and/or…

Solar and Stellar Astrophysics · Physics 2022-06-08 B. M. Shergelashvili , E. Philishvili , S. Buitendag , S. Poedts , M. Khodachenko

The brightness of the emission from coronal loops in the solar atmosphere is strongly dependent on the temperature and density of the confined plasma. After a release of energy, these loops undergo a heating and upflow phase, followed by a…

Solar and Stellar Astrophysics · Physics 2019-03-20 C. D. Johnston , S. J. Bradshaw

Downflows at supersonic speeds have been observed in the transition region (TR) above sunspots for more than three decades. These downflows are often seen in different TR spectral lines above sunspots. We have performed a statistical…

Solar and Stellar Astrophysics · Physics 2018-06-27 Tanmoy Samanta , Hui Tian , Debi Prasad Choudhary

We report multi-wavelength ultraviolet observations taken with the IRIS satellite, concerning the emergence phase in the upper chromosphere and transition region of an emerging flux region (EFR) embedded in the unipolar plage of active…

Solar and Stellar Astrophysics · Physics 2019-07-17 S. L. Guglielmino , F. Zuccarello , P. R. Young , P. Romano , M. Murabito
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