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The Sun's corona is millions of degrees hotter than its 5,000 K photosphere. This heating enigma is typically addressed by invoking the deposition at coronal heights of non-thermal energy generated by the interplay between convection and…

Solar and Stellar Astrophysics · Physics 2009-08-11 Bart De Pontieu , Scott W. McIntosh , Viggo H. Hansteen , Carolus J. Schrijver

Context: Long-period intensity pulsations were recently detected in the EUV emission of coronal loops, and have been attributed to cycles of plasma evaporation and condensation driven by thermal non-equilibrium (TNE). Numerical simulations…

Solar and Stellar Astrophysics · Physics 2020-02-12 Gabriel Pelouze , Frédéric Auchère , Karine Bocchialini , Clara Froment , Susanna Parenti , Elie Soubrié

The solar corona consists of a million-degree Kelvin plasma. A complete understanding of this phenomenon demands the study of Quiet Sun (QS) regions. In this work, we study QS regions in the 171 {\AA}, 193 {\AA} and 211 {\AA} passbands of…

Solar and Stellar Astrophysics · Physics 2021-08-02 Vishal Upendran , Durgesh Tripathi

The heating of the solar corona and the puzzle of the slender high reaching magnetic loops seen in observations from the Transition Region And Coronal Explorer(TRACE) has been investigated through 3D numerical simulations, and found to be…

Astrophysics · Physics 2007-05-23 Boris V. Gudiksen , Aake Nordlund

High resolution spectra from the Hinode EUV Imaging Spectrometer (EIS) have revealed that coronal spectral line profiles are sometimes asymmetric, with a faint enhancement in the blue wing on the order of 100 km/s. These asymmetries could…

Solar and Stellar Astrophysics · Physics 2015-06-11 David H. Brooks , Harry P. Warren

We study the magnetic properties of small-scale transients in coronal hole. We found all brightening events are associated with bipolar regions and caused by magnetic flux emergence followed by cancellation with the pre-existing and newly…

Solar and Stellar Astrophysics · Physics 2014-05-16 Z. Huang , M. S. Madjarska , J. G. Doyle , D. A. Lamb

Coronal loops are the basic structures of the solar transition region and corona. The understanding of physical mechanism behind the loop heating, plasma flows, and filling are still considered a major challenge in the solar physics. The…

Solar and Stellar Astrophysics · Physics 2015-02-24 G. R. Gupta , Durgesh Tripathi , Helen E. Mason

The Extreme ultraviolet Imaging Spectrometer (EIS) on board Hinode is the first solar telescope to obtain wide slit spectral images that can be used for detecting Doppler flows in transition region and coronal lines on the Sun and to relate…

Astrophysics · Physics 2009-11-13 D. E. Innes , R. Attie , H. Hara , M. S. Madjarska

Measurements of the temperature and density structure of the solar corona provide critical constraints on theories of coronal heating. Unfortunately, the complexity of the solar atmosphere, observational uncertainties, and the limitations…

Solar and Stellar Astrophysics · Physics 2009-07-22 Harry P. Warren , David H. Brooks

Jets (transient/collimated plasma ejections) occur frequently throughout the solar corona and contribute mass/energy to the corona and solar wind. By combining numerical simulations and high-resolution observations, we have made substantial…

Solar and Stellar Astrophysics · Physics 2019-03-20 Pankaj Kumar , Judith T. Karpen , Spiro K. Antiochos , Peter F. Wyper , C. Richard DeVore , Craig E. DeForest

Oscillations of coronal loops in the Sun have been reported in both imaging and spectral observations at the onset of flares. Images reveal transverse oscillations, whereas spectra detect line-of-sight velocity or Doppler-shift…

Solar and Stellar Astrophysics · Physics 2015-05-27 Danica Tothova , Davina Innes , Guillermo Stenborg

Collimated ejections of plasma called "coronal hole jets" are commonly observed in polar coronal holes. However, such coronal jets are not only a specific features of polar coronal holes but they can also be found in coronal holes appearing…

Solar and Stellar Astrophysics · Physics 2015-05-18 G. Nistico' , V. Bothmer , S. Patsourakos , G. Zimbardo

We present observations of transient active region heating events observed with the Extreme Ultraviolet Imaging Spectrometer (EIS) and X-ray Telescope (XRT) on Hinode. This initial investigation focuses on NOAA active region 10940 as…

The aim of this work is to determine the multi-thermal characteristics and plasma energetics of an eruptive plasmoid and occulted flare observed by Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA). We study an event from…

Solar and Stellar Astrophysics · Physics 2015-06-12 I. G. Hannah , E. P. Kontar

Using ALMA observations, we performed the first systematic survey for transient brightenings (i.e. weak, small-scale episodes of energy release) in the quiet solar chromosphere at 3 mm. Our dataset included images of six 87'' x 87'' regions…

Solar and Stellar Astrophysics · Physics 2020-07-01 A. Nindos , C. E. Alissandrakis , S. Patsourakos , T. S. Bastian

To study motions and oscillations in the solar chromosphere and at the transition region (TR) level we analyze some extreme Doppler shifts observed off-limb with the Interface Region Imaging Spectrograph (IRIS). Raster scans and slit-jaw…

Solar and Stellar Astrophysics · Physics 2019-09-25 E. Tavabi , S. Koutchmy

Coronal Holes (CHs) have subdued intensity and net blueshifts when compared to Quiet Sun (QS) at coronal temperatures. At transition region temperatures, such differences are obtained for regions with identical photospheric absolute…

Solar and Stellar Astrophysics · Physics 2021-11-30 Vishal Upendran , Durgesh Tripathi

Stellar flares affect all atmospheric layers from the photosphere over chromosphere and transition region up into the corona. Simultaneous observations in different spectral bands allow to obtain a comprehensive picture of the environmental…

Solar and Stellar Astrophysics · Physics 2015-05-18 Carolin Liefke , Birgit Fuhrmeister , Juergen H. M. M. Schmitt

We investigate the effect of coronal temperature on the formation process of solar chromospheric jets using two-dimensional magnetohydrodynamic simulations of the region from the upper convection zone to the lower corona. We develop a new…

Solar and Stellar Astrophysics · Physics 2015-10-28 H. Iijima , T. Yokoyama

We investigate the thermal, kinematic and magnetic structure of small-scale heating events in an emerging flux region (EFR). We use high-resolution multi-line observations (including Ca II 8542~\AA, Ca II K, and Fe I 6301~\AA line pair) of…

Solar and Stellar Astrophysics · Physics 2023-09-14 Rahul Yadav , Maria D. Kazachenko , Andrey N. Afanasyev , Jaime de la Cruz Rodríguez , Jorrit Leenaarts
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