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We have carried out a comprehensive study of the temperature structure of plasmoids, which successively occurred in recurrent active region jets. The multithermal plasmoids were seen to be travelling along the multi-threaded spire as well…

Solar and Stellar Astrophysics · Physics 2022-11-16 Sargam M. Mulay , Durgesh Tripathi , Helen Mason , Giulio Del Zanna , Vasilis Archontis

We present the observational evidence of the existence of a double-decker filament channel (FC) by using observations in extreme ultraviolet and H{\alpha} wavelengths. For both FCs, the east foot-point roots in the active region (AR), while…

Solar and Stellar Astrophysics · Physics 2025-11-27 Yin Zhang , Baolin Tan , Quan Wang , Jing Huang , Zhe Xu , Kanfan Ji , Xiao Yang , Jie Chen , Xianyong Bai , Zhenyong Hou , Yuanyong Deng

Multiwavelength observations of the propagating disturbances (PDs), discovered by Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO), are analyzed to determine its driving mechanism and physical nature. Two magnetic…

We study the coronal dimming caused by the fast halo CME (deprojected speed v =1250 km s $^{-1})$ associated with the C3.7 two-ribbon flare on 2012 September 27, using Hinode/EIS spectroscopy and SDO/AIA Differential Emission Measure (DEM)…

Solar and Stellar Astrophysics · Physics 2019-07-17 Astrid M. Veronig , Peter Gömöry , Karin Dissauer , Manuela Temmer , Kamalam Vanninathan

A significant impediment to solving the coronal heating problem is that we currently only observe active region (AR) loops in their cooling phase. Previous studies showed that the evolution of cooling loop densities and apex temperatures…

Solar and Stellar Astrophysics · Physics 2024-01-10 David H. Brooks , Jeffrey W. Reep , Ignacio Ugarte-Urra , John E. Unverferth , Harry P. Warren

We present a study of the temporal evolution of coronal loops in active regions and its implications for the dynamics in coronal loops. We analyzed images of the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) at…

Solar and Stellar Astrophysics · Physics 2011-08-09 S. Kamio , H. Peter , W. Curdt , S. K. Solanki

It is well-known that extreme ultraviolet emission emitted at the solar surface is absorbed by overlying cool plasma. Especially in active regions dark lanes in EUV images suggest that much of the surface activity is obscured. Simultaneous…

Solar and Stellar Astrophysics · Physics 2016-12-14 N. -H. Chen , D. E. Innes

We present mid-infrared SOFIA/EXES spectroscopy of Europa, seeking direct evidence of the presence of water vapor arising from plumes venting from the surface of Europa. We place quantitatively useful upper limits on the strength of water…

Earth and Planetary Astrophysics · Physics 2019-01-30 William Sparks , M. Richter , C. deWitt , E. Montiel , N. Dello Russo , J. Grunsfeld , M. A. McGrath , H. Weaver , K. P. Hand , E. Bergeron , W. Reach

The properties of solar flare plasma can be determined from the observation of optically thin lines. The emitting ion distribution determines the shape of the line, with an isothermal Maxwellian ion distribution producing a Gaussian…

Solar and Stellar Astrophysics · Physics 2016-05-25 Natasha Jeffrey , Lyndsay Fletcher , Nicolas Labrosse

Spectral line widths are often observed to be larger than can be accounted for by thermal and instrumental broadening alone. This excess broadening is a key observational constraint for both nanoflare and wave dissipation models of coronal…

Solar and Stellar Astrophysics · Physics 2016-03-23 David H. Brooks , Harry P. Warren

This thesis strives to improve our understanding of solar activity, specifically the behaviour of solar flares and coronal mass ejections. An investigation into the hydrodynamic evolution of a confined solar flare was carried out using…

Solar and Stellar Astrophysics · Physics 2012-10-19 Claire L. Raftery

This paper presents a detailed study of excess line broadening in EUV emission lines during the impulsive phase of a C-class solar flare. In this work, which utilizes data from the EUV Imaging Spectrometer (EIS) onboard Hinode, the…

Solar and Stellar Astrophysics · Physics 2012-02-09 Ryan O. Milligan

The properties expected of "hot" non-flaring plasmas due to nanoflare heating in active regions are investigated using hydrodynamic modeling tools, including a two-fluid development of the EBTEL code. Here we study a single nanoflare and…

Solar and Stellar Astrophysics · Physics 2016-09-28 W. T. Barnes , P. J. Cargill , S. J. Bradshaw

Context: A large number of the small and the short-lived EUV brightenings have been detected in the quiet Sun (QS) over the past three years, by the High Resolution Imager of the Extreme Ultraviolet Imager (HRIEUV) on board Solar Orbiter.…

Solar and Stellar Astrophysics · Physics 2024-08-09 A. Dolliou , S. Parenti , K. Bocchialini

A sign reversal of the directed flow parameter $v_1$ in the central rapidity region in Au+Au collisions at $\sqrt s =200$~AGeV is predicted. This anti-flow is shown to be linked to the expansion of the hot matter created. In line with this…

High Energy Physics - Phenomenology · Physics 2014-11-17 M. Bleicher , H. Stöcker

We present a new analysis of very deep Chandra observations of the galaxy cluster Abell 1795. Utilizing nearly 750 ks of net ACIS imaging, we are able to resolve the thermodynamic structure of the Intracluster Medium (ICM) on length scales…

Astrophysics of Galaxies · Physics 2015-06-22 S. Ehlert , M. McDonald , E. D. Miller , L. P. David , M. W. Bautz

Nanoflares in quiet-Sun regions during solar cycle 24 are studied with the best available plasma diagnostics to derive their energy distribution and contribution to coronal heating during different levels of solar activity. Extreme…

Solar and Stellar Astrophysics · Physics 2022-05-25 Stefan Purkhart , Astrid M. Veronig

We performed the temperature diagnostics using inversions of data from nine spectroscopic observations obtained with the IRIS spectrograph in the MgII h & k lines. The sensitivity to the temperature of the emission peaks of these lines was…

Solar and Stellar Astrophysics · Physics 2024-01-29 M. Kriginsky , R. Oliver

High-spectral resolution observations using the VTT echelle spectrograph in the chromospheric H$\alpha$ line were obtained in the early growth phase of active region NOAA 12722. Noise-stripped H$\alpha$ line profiles yield maps of line-core…

Solar and Stellar Astrophysics · Physics 2020-07-08 M. Verma , C. Denker , A. Diercke , C. Kuckein , H. Balthasar , E. Dineva , I. Kontogiannis , P. S. Pal , M. Sobotka

With increasing solar activity since 2010, many flares from the backside of the Sun have been observed by the Extreme Ultraviolet Imager (EUVI) on either of the twin STEREO spacecraft. Our objective is to estimate their X-ray peak fluxes…

Solar and Stellar Astrophysics · Physics 2013-04-16 N. V. Nitta , M. J. Aschwanden , P. F. Boerner , S. L. Freeland , J. R. Lemen , J. -P. Wuelser