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Related papers: A Comparison of EIT and TRACE Loop Widths

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Magnetic field extrapolation is an important tool to study the three-dimensional (3D) solar coronal magnetic field which is difficult to directly measure. Various analytic models and numerical codes exist but their results often drastically…

Solar and Stellar Astrophysics · Physics 2017-06-28 Aiying Duan , Chaowei Jiang , Qiang Hu , Huai Zhang , G. Allen Gary , S. T. Wu , Jinbin Cao

We report results of an in-depth numerical investigation of three-dimensional projection effects which could influence the observed loop-like structures in an optically thin solar corona. Several archetypal emitting geometries are tested,…

Solar and Stellar Astrophysics · Physics 2023-11-13 Vadim M. Uritsky , James A. Klimchuk

"EIT waves" are freely-propagating global pulses in the low corona which are strongly associated with the initial evolution of coronal mass ejections (CMEs). They are thought to be large-amplitude, fast-mode magnetohydrodynamic waves…

Solar and Stellar Astrophysics · Physics 2017-07-19 David M. Long , Gherardo Valori , David Pérez-Suárez , Richard J. Morton , Alberto Marcos Vásquez

More and more evidence indicates that "EIT waves" are strongly related to coronal mass ejections (CMEs). However, it is still not clear how the two phenomena are related to each other. We investigate a CME event on 1997 September 9, which…

Solar and Stellar Astrophysics · Physics 2011-02-11 P. F. Chen

The 1998 April 20 spectral line data from the Coronal Diagnostics Spectrometer (CDS) on the {\it Solar and Heliospheric Observatory} (\SOHO) shows a coronal loop on the solar limb. Our original analysis of these data showed that the plasma…

Astrophysics · Physics 2009-11-11 J. T. Schmelz , K. Nasraoui , V. L. Richardson , P. J. Hubbard , C. R. Nevels , J. E. Beene

We explore the link between solar energetic particles (SEPs) observed at 1 AU and large-scale disturbances propagating in the solar corona, named after the Extreme ultraviolet Imaging Telescope (EIT) as EIT waves, which trace the lateral…

Solar and Stellar Astrophysics · Physics 2015-06-18 R. Miteva , K. -L. Klein , I. Kienreich , M. Temmer , A. Veronig , O. E. Malandraki

Coronal holes are usually defined as dark structures as seen in the extreme ultraviolet and X-ray spectrum which are generally associated with open magnetic field. Deriving reliably the coronal hole boundary is of high interest, as its…

One puzzling observed property of coronal loops is that they are of roughly constant thickness along their length. Various studies have found no consistent pattern of width variation along the length of loops observed by TRACE and SOHO.…

Solar and Stellar Astrophysics · Physics 2009-11-13 Joseph E. Plowman , Charles C. Kankelborg , Dana W. Longcope

Coronal loops are fundamental building blocks of the solar active regions and the corona. Therefore, a clear understanding of the physics of coronal loops will help us understand the physics of active region heating in particular and…

Solar and Stellar Astrophysics · Physics 2011-02-11 D. Tripathi , H. E. Mason , B. N. Dwivedi , G. Del Zanna , P. R. Young

The relationships among coronal loop structures at different temperatures is not settled. Previous studies have suggested that coronal loops in the core of an active region are not seen cooling through lower temperatures and therefore are…

Solar and Stellar Astrophysics · Physics 2011-02-11 Ignacio Ugarte-Urra , Harry P. Warren , David H. Brooks

Aims: To understand the contribution of active region and flare plasmas to the $\lambda$195 channels of SOHO/EIT (Extreme-ultraviolet Imaging Telescope) and TRACE (Transition Region and Coronal Explorer). Methods: We have analysed an M8…

Astrophysics · Physics 2009-06-25 D. Tripathi , G. Del Zanna , H. E. Mason , C. Chifor

We compare coronagraph concepts and investigate their behavior and suitability for planet finder projects with Extremely Large Telescopes (ELTs, 30-42 meters class telescopes). For this task, we analyze the impact of major error sources…

Astrophysics · Physics 2009-11-13 P. Martinez , A. Boccaletti , M. Kasper , C. Cavarroc , N. Yaitskova , T. Fusco , C. Verinaud

Coronal loops in active regions are the subjects of intensive investigation, but the important diffuse 'unresolved' emission in which they are embedded has received relatively little attention. Here we measure the densities and emission…

Solar and Stellar Astrophysics · Physics 2019-03-06 David H. Brooks

Aims. To determine the solar transition region and coronal radius at EUV wavelengths and its time evolution during Solar Cycle XXIII. Methods. We use daily 30.4 and 17.1 nm images obtained by the Extreme Ultraviolet Imager (EIT) aboard the…

Astrophysics · Physics 2009-11-13 C. G. Giménez de Castro , A. C. V. Saraiva , J. E. R. Costa , C. L. Selhorst

As the observational signature of the footprints of solar magnetic field lines open into the heliosphere, coronal holes provide a critical measure of the structure and evolution of these lines. Using a combination of Solar and Heliospheric…

Solar and Stellar Astrophysics · Physics 2016-12-23 Chris Lowder , Jiong Qiu , Robert Leamon

Data from recent numerical simulations of the solar corona and transition region are analysed and the magnetic field connection between the low corona and the photosphere is found to be close to that of a potential field. The fieldline to…

Astrophysics · Physics 2014-10-13 B. V. Gudiksen , Å. Nordlund

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 transition region between the Sun's corona and chromosphere is important to the mass and energy transfer from the lower atmosphere to the corona; consequently, this region has been studied intensely with ultraviolet (UV) and extreme…

Solar and Stellar Astrophysics · Physics 2023-02-08 C. Gontikakis , S. K. Antiochos , P. R. Young

We present a first systematic study on the cross-sectional temperature structure of coronal loops using the six coronal temperature filters of the Atmospheric Imaging Assembly (AIA) instrument on the Solar Dynamics Observatory (SDO). We…

Solar and Stellar Astrophysics · Physics 2015-05-27 Markus J. Aschwanden , Paul Boerner

For the first time, the kinematic evolution of a coronal wave over the entire solar surface is studied. Full Sun maps can be made by combining images from the Solar Terrestrial Relations Observatory satellites, Ahead and Behind, and the…

Solar and Stellar Astrophysics · Physics 2015-06-05 Oscar Olmedo , Angelos Vourlidas , Jie Zhang , Xin Cheng