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Related papers: Inferring the Coronal Density Irregularity from EU…

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Why the tenuous solar outer atmosphere, or corona, is much hotter than the underlying layers remains one of the greatest challenge for solar modeling. Detailed diagnostics of the coronal thermal structure come from extreme ultraviolet (EUV)…

Solar and Stellar Astrophysics · Physics 2018-05-02 Gregory Fleishman , Sophie Musset , Véronique Bommier , Lindsay Glesener

Determining the relative brightness of the solar corona is one of the most critical stages in solar eclipse studies. For this purpose, images taken with different exposures and polarization angles in white-light observations are used. The…

Solar and Stellar Astrophysics · Physics 2017-12-01 Hikmet Çakmak

Observations of transition region emission in solar active regions represent a powerful tool for determining the properties of hot coronal loops. In this Letter we present the analysis of new observations of active region moss taken with…

The distribution of the coronal electron density at different distances from the Sun strongly influences the physical processes in the solar corona and is therefore a very important topic in solar physics. Most methods, including radio…

To understand its evolution and the effects of its eruptive events, the Sun is permanently monitored by multiple satellite missions. The optically-thin emission of the solar plasma and the limited number of viewpoints make it challenging to…

Filaments may be mistaken for coronal holes when observed in extreme ultraviolet (EUV) images; however, a closer and more careful look reveals that their photometric properties are different. The combination of EUV images with photospheric…

Solar and Stellar Astrophysics · Physics 2017-04-04 Judith Palacios , Consuelo Cid , Elena Saiz , Yolanda Cerrato , Antonio Guerrero

EUV images of Comet Lovejoy (C/2011 W3) from the AIA show striations related to the magnetic field structure in both open and closed magnetic regions. The brightness contrast implies coronal density contrasts of at least a factor of 6…

Solar and Stellar Astrophysics · Physics 2015-06-19 J. C. Raymond , P. I. McCauley , S. R. Cranmer , C. Downs

Active region EUV loops are believed to trace a subset of magnetic field lines through the corona. Malanushenko et al. (2009) proposed a method, using loop images and line-of-sight photospheric magnetograms, to infer the three-dimensional…

Solar and Stellar Astrophysics · Physics 2021-05-27 Marika I. McCarthy , Dana W. Longcope , Anna Malanushenko

The solar corona is host to a continuous flow of propagating disturbances (PD). These are continuous and ubiquitous across broad regions of the corona, including the quiet Sun. The aim of this paper is to present an improved, efficient…

Solar and Stellar Astrophysics · Physics 2022-08-31 Huw Morgan , Marianna Korsos

This is the second of a series of three papers that present a methodology with the aim of creating a set of maps of the coronal density over a period of many years. This paper describes a method for reconstructing the coronal electron…

Solar and Stellar Astrophysics · Physics 2019-08-22 Huw Morgan

Decaying active region 10942 is investigated from 4:00-16:00 UT on February 24, 2007 using a suite of EUV observing instruments. Results from Hinode/EIS, STEREO and TRACE show that although the active region has decayed and no sunspot is…

Solar and Stellar Astrophysics · Physics 2015-05-30 Jason Scott , P. C. H. Martens , David McKenzie

The solar corona is the origin of very dynamic events that are mostly produced in active regions (AR) and coronal holes (CH). The exact location of these large-scale features can be determined by applying image-processing approaches to…

Solar and Stellar Astrophysics · Physics 2016-04-19 Saeid Arish , Mohsen Javaherian , Hossein Safari , Ali Amiri

There is a pressing need to model X-ray Ultra-Violet (XUV: 1-30 nm) stellar irradiances, given the scarcity of current measurements. One of the measurable effects of a stellar cycle is the significant (more than one order of magnitude)…

Solar and Stellar Astrophysics · Physics 2025-04-14 E. Deliporanidou , G. Del Zanna , T. N. Woods , D. Woodraska

Within the quiet Sun corona imaged at 1 MK, much of the field of view consists of diffuse emission that appears to lack the spatial structuring that is so evident in coronal loops or bright points. We seek to determine if these diffuse…

The total solar eclipse of August 21st, 2017 was observed with a Digital Single Lens Reflex (DSLR) camera equipped with a linear polarizing filter. A method was developed to combine images acquired with 15 different exposure times (from…

Solar and Stellar Astrophysics · Physics 2020-12-09 Alessandro Bemporad

We review the coronal visible and infrared lines, collecting previous observations, and comparing, whenever available, observed radiances with those predicted by various models: the quiet Sun, a moderately active Sun, and an active region…

Solar and Stellar Astrophysics · Physics 2018-01-10 Giulio Del Zanna , Edward E. DeLuca

The plasma parameters such as the electron density and temperature plays a key role in the dynamics of the solar atmosphere. These characteristics are important in solar physics, because they can help to understand the physics in the solar…

Solar and Stellar Astrophysics · Physics 2018-04-12 J. M Rodríguez Gómez , L. Vieira , A. Dal Lago , J. Palacios

In this study, we describe and evaluate shape measures for distinguishing between coronal holes and filament channels as observed in Extreme Ultraviolet (EUV) images of the Sun. For a set of well-observed coronal hole and filament channel…

Solar and Stellar Astrophysics · Physics 2014-08-13 M. Reiss , M. Temmer , T. Rotter , S. J. Hofmeister , A. M. Veronig

Coronal holes are regions on the Sun's surface that map the foot-prints of open magnetic field lines. We have developed an automated routine to detect and track boundaries of long-lived coronal holes using full-disk EUV images obtained by…

Solar and Stellar Astrophysics · Physics 2015-02-24 Chris Lowder , Jiong Qiu , Robert Leamon , Yang Liu

Structures in the solar corona are the main drivers of space weather processes that might directly or indirectly affect the Earth. Thanks to the most recent space-based solar observatories, with capabilities to acquire high-resolution…

Solar and Stellar Astrophysics · Physics 2021-09-23 Šimon Mackovjak , Martin Harman , Viera Maslej-Krešňáková , Peter Butka