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Related papers: Modeling X-ray Loops and EUV "Moss" in an Active R…

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The High Resolution Imager (HRI_EUV) telescope of the Extreme Ultraviolet Imager (EUI) instrument onboard Solar Orbiter has observed EUV brightenings, so-called campfires, as fine-scale structures at coronal temperatures. The goal of this…

Solar and Stellar Astrophysics · Physics 2022-10-18 Krzysztof Barczynski , Karen A. Meyer , Louise K. Harra , Duncan H. Mackay , Frederic Auchere , David Berghmans

In this paper we further develop a model for the heating of coronal loops by Alfven wave turbulence (AWT). The Alfven waves are assumed to be launched from a collection of kilogauss flux tubes in the photosphere at the two ends of the loop.…

Solar and Stellar Astrophysics · Physics 2017-11-08 Adriaan A. van Ballegooijen , Mahboubeh Asgari-Targhi , Alexander Voss

Observational measurements of active region emission measures contain clues to the time-dependence of the underlying heating mechanism. A strongly non-linear scaling of the emission measure with temperature indicates a large amount of hot…

Solar and Stellar Astrophysics · Physics 2015-06-11 Stephen J. Bradshaw , James A. Klimchuk , Jeffrey W. Reep

Two recent works have analyzed a solar large and steady coronal loop observed with Yohkoh/SXT in two filter passbands to infer the distribution of the heating along it. Priest et al. (2000) modelled the distribution of the temperature…

Astrophysics · Physics 2009-11-07 F. Reale

Context: The location of coronal heating in magnetic loops has been the subject of a long-lasting controversy: does it occur mostly at the loop footpoints, at the top, is it random, or is the average profile uniform? Aims: We try to address…

Astrophysics · Physics 2009-11-13 E. Buchlin , P. J. Cargill , S. J. Bradshaw , M. Velli

MHD kink instability can trigger the fragmentation of a twisted magnetic flux tube into small-scale current sheets that dissipate as aperiodic impulsive heating events. This instability propagates as an avalanche to nearby flux tubes and…

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

The EUI instrument on the Solar Orbiter spacecraft has obtained the most stable, high-resolution images of the solar corona from its orbit with a perihelion near 0.4 AU. A sequence of 360 images obtained at 17.1 nm, between 25-Oct-2022…

Solar and Stellar Astrophysics · Physics 2023-09-12 Philip G. Judge

The shape of the spectral energy distribution of active galaxies in the EUV--soft X-ray band (13.6 eV to 1 keV) is uncertain because obscuration by dust and gas can hamper our view of the continuum. To investigate the shape of the spectral…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 M. Meléndez , S. B. Kraemer , K. A. Weaver , R. F. Mushotzky

The velocity pattern of a fan loop structure within a solar active region over the temperature range 0.15-1.5 MK is derived using data from the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. The loop is aligned towards the…

Solar and Stellar Astrophysics · Physics 2015-05-28 P. R. Young , B. O'Dwyer , H. E. Mason

The SDO EUV observations have revealed interesting characteristics of warm coronal emissions, which peak soon after the hot coronal X-ray emissions peak during a flare and then sometimes peak for a second time hours after the X-ray flare…

Solar and Stellar Astrophysics · Physics 2015-06-18 Thomas N. Woods

We model nanoflare heating of extrapolated active-region coronal loops via the acceleration of electrons and protons in Harris-type current sheets. The kinetic energy of the accelerated particles is estimated using semi-analytical and…

Solar and Stellar Astrophysics · Physics 2015-06-16 C. Gontikakis , S. Patsourakos , C. Efthymiopoulos , A. Anastasiadis , M. K. Georgoulis

We aim to reproduce the structure of the corona above a solar active region as seen in the extreme ultraviolet (EUV) using a three-dimensional magnetohydrodynamic (3D MHD) model. The 3D MHD data-driven model solves the induction equation…

Solar and Stellar Astrophysics · Physics 2019-04-30 Jörn Warnecke , Hardi Peter

EUV imaging observations from several space missions (SOHO/EIT, TRACE, and SDO/AIA) have revealed a presence of propagating intensity disturbances in solar coronal loops. These disturbances are typically interpreted as slow magnetoacoustic…

Solar and Stellar Astrophysics · Physics 2018-01-24 Elena Provornikova , Leon Ofman , Tongjiang Wang

Short heat pulses can trigger plasma pressure fronts inside closed magnetic tubes in the corona. The alternation of condensations and rarefactions from the pressure modes drive large-amplitude pulsations in the plasma emission. Here we show…

Solar and Stellar Astrophysics · Physics 2019-11-06 Fabio Reale , Paola Testa , Antonino Petralia , Dmitrii Y. Kolotkov

Using {\em RHESSI} hard X-ray imaging spectroscopy observations, we analyze electron flux maps for a number of extended coronal loop flares. For each event, we fit a collisional model with an extended acceleration region to the observed…

Solar and Stellar Astrophysics · Physics 2015-06-05 Jingnan Guo , A. Gordon Emslie , Anna Maria Massone , Michele Piana

The solar corona is much hotter than the photosphere and chromosphere, but the physical mechanism responsible for heating the coronal plasma remains unidentified yet. The thermal microwave emission, which is produced in strong magnetic…

Solar and Stellar Astrophysics · Physics 2025-08-27 Alexey A. Kuznetsov , Gregory D. Fleishman , Gelu M. Nita , Sergey A. Anfinogentov

In order to better understand the possibility of coronal heating by MHD waves, we analyze Fe xii 195.12{\AA} data observed with EUV Imaging Spectrometer (EIS) onboard Hinode. We performed a Fourier analysis of EUV intensity and Doppler…

Solar and Stellar Astrophysics · Physics 2015-05-19 Naomasa Kitagawa , Takaaki Yokoyama , Shinsuke Imada , Hirohisa Hara

We report for the first time the detection of thermal free-free emission from post-flare loops at 34GHz in images from the Nobeyama Radioheliograph (NoRH). We studied 8 loops, 7 of which were from regions with extremely strong coronal…

Solar and Stellar Astrophysics · Physics 2024-06-24 Costas E. Alissandrakis , Gregory D. Fleishman , Viktor V. Fedenev , Stephen M. White , Alexander T. Altyntsev

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
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