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We performed a systematic study of the Doppler shifts and electron densities measured in an EUV bright point (hereafter BP) observed in more than 10 EUV lines with formation temperatures from log (T/K) p 4.5 to 6.3. Those parts of a BP seen…

Solar and Stellar Astrophysics · Physics 2011-02-11 Hui Tian , Werner Curdt , Eckart Marsch , Jiansen He

Nanoflares are impulsive energy releases by magnetic reconnection in the braided coronal magnetic field, which is a potential mechanism for heating the corona. However, there are still sporadic observations of the interchange of braiding…

Solar and Stellar Astrophysics · Physics 2023-11-01 Y. Bi , J. J. Yang , Y. Qin , Z. P. Qiang , J. C. Hong , B. Yang , Z. Xu , H. Liu , K. F. Ji

Solar flares are associated with intense soft X-ray emission generated by the hot flaring plasma. Kink unstable twisted flux-ropes provide a source of magnetic energy which can be released impulsively and account for the flare plasma…

Solar and Stellar Astrophysics · Physics 2015-03-25 R. F. Pinto , N. Vilmer , A. S. Brun

We show that the coronal heating and the acceleration of the fast solar wind in the coronal holes are natural consequence of the footpoint fluctuations of the magnetic fields at the photosphere by one-dimensional, time-dependent, and…

Astrophysics · Physics 2007-05-23 Takeru K. Suzuki , Shu-ichiro Inutsuka

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

Surges have regularly been observed mostly in H$_{\alpha}$ 6563~{\AA} and Ca~{\sc ii} 8542~{\AA}. However, surge$'$s response to other prominent lines of the interface-region (Mg~{\sc ii} k 2796.35~{\AA} $\&$ h 2803.52~{\AA}, O~{\sc iv}…

Solar and Stellar Astrophysics · Physics 2021-07-07 Pradeep Kayshap , Rajdeep Singh Payal , Sharad C. Tripathi , Harihara Padhy

We detail experimental results inferring ionization and temperature for warm dense copper plasmas at several times solid density (15 to 25 g/cm$^3$) and temperatures of 10 to 21 eV. Experiments performed at the OMEGA Laser Facility generate…

Strongly damped Doppler shift oscillations are observed frequently associated with flarelike events in hot coronal loops. In this paper, a review of the observed properties and the theoretical modeling is presented. Statistical measurements…

Solar and Stellar Astrophysics · Physics 2014-04-24 Tongjiang Wang

We model the hydrodynamic evolution of the plasma confined in a coronal loop, 30000 km long, subject to the heating of nanoflares due to intermittent magnetic dissipative events in the MHD turbulence produced by loop footpoint motions. We…

Astrophysics · Physics 2009-11-13 F. Reale , G. Nigro , F. Malara , G. Peres , P. Veltri

The relative amount of high temperature plasma has been found to be a useful diagnostic to determine the frequency of coronal heating on sub-resolution structures. When the loops are infrequently heated, a broad emission measure (EM) over a…

Our aim is to determine the plasma properties of a coronal bright point and compare its magnetic topology extrapolated from magnetogram data with its appearance in X-ray images. We analyse spectroscopic data obtained with EIS/Hinode, Ca II…

Astrophysics · Physics 2008-10-07 D. Pérez-Suárez , R. C. Maclean , J. G. Doyle , M. S. Madjarska

We developed an automated procedure for the identification of transient brightenings in images from the X-ray telescope on-board Hinode taken with an Al Poly filter in the equatorial coronal holes, polar coronal holes, and the quiet Sun…

Solar and Stellar Astrophysics · Physics 2015-05-18 S. Subramanian , M. S. Madjarska , J. G. Doyle

Recent analysis of high-cadence white-light images taken by the Solar-Terrestrial RElations Observatory (STEREO) near solar maximum has revealed that outflowing density structures are released in an ubiquitous manner in the solar wind. The…

Solar and Stellar Astrophysics · Physics 2020-04-22 Léa Griton , Rui F. Pinto , Nicolas Poirier , Athanasios Kouloumvakos , Michaël Lavarra , Alexis P. Rouillard

The light curves of solar coronal loops often peak first in channels associated with higher temperatures and then in those associated with lower. The time delays between the different narrowband EUV channels have been measured for many…

Solar and Stellar Astrophysics · Physics 2017-03-22 Roberto Lionello , Caroline E. Alexander , Amy R. Winebarger , Jon A. Linker , Zoran Mikić

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

We examine the hypothesis that plasma associated with "Type II" spicules is heated to coronal temperatures, and that the upward moving hot plasma constitutes a significant mass supply to the solar corona. 1D hydrodynamical models including…

Solar and Stellar Astrophysics · Physics 2015-06-03 Philip G. Judge , Bart de Pontieu , Scott McIntosh , Kosovare Olluri

New instruments sensitive to chromospheric radiation at X-ray, UV, Visible, IR, and sub-mm wavelengths have become available that significantly enhance our ability to understand the bi-directional flow of energy through the chromosphere. We…

Solar and Stellar Astrophysics · Physics 2022-07-27 Adam R. Kobelski , Lucas A. Tarr , Sarah A. Jaeggli , Nicholas Luber , Harry P. Warren , Sabrina L. Savage

We analyze and model a C5.7 two-ribbon solar flare observed by SDO, Hinode and GOES on 2011 December 26. The flare is made of many loops formed and heated successively over one and half hours, and their footpoints are brightened in the UV…

Solar and Stellar Astrophysics · Physics 2018-04-04 Chunming Zhu , Jiong Qiu , Dana W. Longcope

As one of the most spectacular energy release events in the solar system, solar flares are generally powered by magnetic reconnection in the solar corona. As a result of the re-arrangement of magnetic field topology after the reconnection…

Solar and Stellar Astrophysics · Physics 2021-03-29 Tanmoy Samanta , Hui Tian , Bin Chen , Katharine K. Reeves , Mark C. M. Cheung , Angelos Vourlidas , Dipankar Banerjee

Coronal rain consists of cool plasma condensations formed in coronal loops as a result of thermal instability. The standard models of coronal rain formation assume that the heating is quasi-steady and localised at the coronal loop…

Solar and Stellar Astrophysics · Physics 2019-10-18 P. Kohutova , E. Verwichte , C. Froment