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We study the correlation heights, which indicate the formation height of Extreme Ultraviolet (EUV) lines in an active region using observations from the EUV Imaging Spectrometer (EIS) and Solar Optical Telescope (SOT) on board…

Solar and Stellar Astrophysics · Physics 2011-02-11 Y. Guo , M. D. Ding , M. Jin , T. Wiegelmann

This paper investigates a quiescent (non-flaring) active region observed on July 13, 2010 in EUV, SXR, and HXRs to search for a hot component that is speculated to be a key signature of coronal heating. We use a combination of RHESSI…

Solar and Stellar Astrophysics · Physics 2019-05-15 Shin-nosuke Ishikawa , Sam Krucker

Plasma composition in flaring regions has been shown to have significant spatial and temporal variations, likely driven by dynamical processes that take place as a consequence of the sudden energy release at the reconnection site. The…

A new approach to investigations of ultra-high energy cosmic rays based on the ground-level measurements of the spectra of local density of EAS muons at various zenith angles is considered. Basic features of the local muon density…

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

We investigate intensity variations and energy deposition in five coronal loops in active region cores. These were selected for their strong variability in the AIA/SDO 94 {\AA} intensity channel. We isolate the hot Fe XVIII and Fe XXI…

Solar and Stellar Astrophysics · Physics 2015-06-19 A. C. Cadavid , J. K. Lawrence , D. J. Christian , D. B. Jess , G. Nigro

We present a multi-wavelength analysis of two flare-related jets on November 13, 2014, using data from SDO/AIA, RHESSI, Hinode/XRT, and IRIS. Unlike most coronal jets where hard X-ray (HXR) emissions are usually observed near the jet base,…

Solar and Stellar Astrophysics · Physics 2022-07-13 Yixian Zhang , Sophie Musset , Lindsay Glesener , Navdeep Panesar , Gregory Fleishman

In this work we investigate the thermal structure of an off-limb active region in various non-flaring areas, as it provides key information on the way these structures are heated. In particular, we concentrate in the very hot component (>3…

Solar and Stellar Astrophysics · Physics 2017-09-06 Susanna Parenti , Giulio del Zanna , Antonino Petralia , Fabio Reale , Luca Teriaca , Paola Testa , Helen E. Mason

I report on observations of a set of magnetic loops above a region with late-phase flux emergence taken by IRIS, Hinode and SDO. The loop system consists of many transition region loop threads with size of 5--12\arcsec\ in length and…

Solar and Stellar Astrophysics · Physics 2019-01-09 Zhenghua Huang

Motivated by dark coronal lanes in SOHO / EIT 284 {\AA} EUV observations we construct and optimize an atmosphere model of the AR 8535 sunspot by adding a cool and dense component in the volume of plasma along open field lines determined…

Solar and Stellar Astrophysics · Physics 2021-10-06 A. Vrublevskis , B. I. Ryabov , S. M. White

We present the study of the X2-class flare which occurred on the 27 October 2014 and was observed with the Interface Region Imaging Spectrograph (IRIS) and the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. Thanks to the high…

Solar and Stellar Astrophysics · Physics 2016-01-27 V. Polito , J. W. Reep , K. K. Reeves , P. J. A. Simões , J. Dudík , G. Del Zanna , H. E. Mason , L. Golub

A large part of the hot corona consists of magnetically confined, bright plasma loops. These observed loops are in turn structured into bright strands. We investigate the relationship between magnetic field geometry, plasma properties and…

Solar and Stellar Astrophysics · Physics 2025-12-22 C. A. Breu , D. I. Pontin , E. Priest , I. De Moortel

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

The Sun's magnetic fields play an important role in various solar phenomena. Solar pores are regions of intensified magnetic field strength compared to the surrounding photospheric environment, and their study can help us better understand…

Solar and Stellar Astrophysics · Physics 2023-06-07 J. I. Campos Rozo , S. Vargas Domínguez , D. Utz , A. M. Veronig , A. Hanslmeier

We present a study of a recurring jet observed on October 31, 2011 by SDO/AIA, Hinode/XRT and Hinode/EIS. We discuss the physical parameters of the jet such as density, differential emission measure, peak temperature, velocity and filling…

Solar and Stellar Astrophysics · Physics 2017-01-25 Sargam M. Mulay , Giulio Del Zanna , Helen Mason

In this work we report on a cold, bright portion of an active region observed by Hinode/EIS. The emitting plasma was very bright at transition region temperatures, and the intensities of lines of ions formed between 10^5-10^6 K were…

Solar and Stellar Astrophysics · Physics 2015-05-13 E. Landi , P. R. Young

Solar inter-network magnetic field is the weakest component of solar magnetism, but contributes most of the solar surface magnetic flux. The study on its origin has been constrained by the inadequate tempo-spatial resolution and sensitivity…

Solar and Stellar Astrophysics · Physics 2015-05-26 Chunlan Jin , Jingxiu Wang

Extracting the temperature of coronal loops is effective in the analysis of solar active region's loops and helps in better understanding of coronal events. To this end, various methods have already been developed like the method developed…

Solar and Stellar Astrophysics · Physics 2019-08-30 Narges Fathalian

A proxy for horizontal electric currents in the solar photosphere was suggested. For a set of evolving active regions (ARs) observed with {\it Solar and Heliospheric Observatory (SOHO)} Michelson Doppler Imager (MDI) in the high resolution…

Astrophysics · Physics 2008-06-11 Valentyna Abramenko

The signatures of energy release and energy transport for a kink-unstable coronal flux rope are investigated via forward modelling. Synthetic intensity and Doppler maps are generated from a 3D numerical simulation. The CHIANTI database is…

Solar and Stellar Astrophysics · Physics 2017-06-21 Ben Snow , Gert J. J. Botha , Stephane Regnier , Richard J. Morton , Erwin Verwichte , Peter R Young