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The characteristic electron densities, temperatures, and thermal distributions of 1MK active region loops are now fairly well established, but their coronal magnetic field strengths remain undetermined. Here we present measurements from a…

Solar and Stellar Astrophysics · Physics 2021-07-14 David H. Brooks , Harry P. Warren , Enrico Landi

A comparison between a Coronal Hole (CH) and the adjacent Quiet-Sun (QS) has been performed using spectroscopic diagnostics of Hinode/ the EUV Imaging Spectrometer (EIS). Coronal funnels play an important role in the formation and…

Solar and Stellar Astrophysics · Physics 2015-11-04 P. Kayshap , D. Banerjee , A. K. Srivastava

The perplexing mystery of what maintains the solar coronal temperature at about a million K, while the visible disc of the Sun is only at 5800 K, has been a long standing problem in solar physics. A recent study by Mondal(2020) has provided…

Solar and Stellar Astrophysics · Physics 2024-02-09 Shabbir Bawaji , Ujjaini Alam , Surajit Mondal , Divya Oberoi

A small blowout jet was observed at the boundary of the south polar coronal hole on 2011 February 8 at around 21:00 UT. Images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) revealed an expanding…

Solar and Stellar Astrophysics · Physics 2015-06-18 Peter R. Young , Karin Muglach

Hot channels (HCs), high temperature erupting structures in the lower corona of the Sun, have been proposed as a proxy of magnetic flux ropes (MFRs) since their initial discovery. However, it is difficult to make definitive proof given the…

Solar and Stellar Astrophysics · Physics 2015-08-06 Hongqiang Song , Yao Chen , Jie Zhang , Xin Cheng , Bing Wang , Qiang Hu , Gang Li , Yuming Wang

Using MHD seismology by observed kink waves, the magnetic field profile of a coronal streamer has been investigated. STEREO-B/EUVI temporal image data on 7 March 2012 shows an evolution of two consecutive EUV waves that interact with the…

Solar and Stellar Astrophysics · Physics 2016-08-17 A. K. Srivastava , Talwinder Singh , Leon Ofman , B. N. Dwivedi

Coronal Bright Points (CBPs) are ubiquitous structures in the solar atmosphere composed of hot small-scale loops observed in EUV or X-Rays in the quiet Sun and coronal holes. They are key elements to understand the heating of the corona;…

Solar and Stellar Astrophysics · Physics 2022-08-24 D. Nóbrega-Siverio , F. Moreno-Insertis

The nature of coronal wave fronts is deeply debated. They are observed in several wavelength bandpasses in spectra, and are frequently interpreted as magnetosonic waves propagating in the lower solar atmosphere. However, they can be…

Solar and Stellar Astrophysics · Physics 2015-06-17 Cecile Delannee , Guy Artzner , Brigitte Schmieder , Susanna Parenti

By measuring the geometrical properties of the coronal mass ejection (CME) flux rope and the leading shock observed on 2010 June 13 by the Solar Dynamics Observatory (SDO) mission's Atmospheric Imaging Assembly (AIA) we determine the…

Solar and Stellar Astrophysics · Physics 2015-05-30 Nat Gopalswamy , Nariaki Nitta , Sachiko Akiyama , Pertti Mäkelä , Seiji Yashiro

Detailed hydrodynamic modeling explained several features of a fragment of the core of a Coronal Mass Ejection observed with SoHO/UVCS at 1.7 Ro on 12 December 1997, but some questions remained unsolved. We investigate the role of the…

Astrophysics · Physics 2007-05-23 P. Pagano , F. Reale , S. Orlando , G. Peres

(abridged) We investigate the long-term evolution of X-ray coronae of solar analogs based on high-resolution X-ray spectroscopy and photometry with XMM-Newton. Six nearby main-sequence G stars with ages between ~0.1 Gyr and \~1.6 Gyr and…

Astrophysics · Physics 2009-11-10 A. Telleschi , M. Guedel , K. Briggs , M. Audard , J. -U. Ness , S. L. Skinner

Central supermassive black holes of active galactic nuclei host hot plasma with a temperature of $10^9$ K, namely coronae. Like the Sun, black hole coronae are theoretically believed to be heated by their magnetic activity, which have never…

High Energy Astrophysical Phenomena · Physics 2018-12-26 Yoshiyuki Inoue , Akihiro Doi

We report flux-resolved spectroscopic analysis of the active galactic nucleus (AGN) ESO 103--035 using \textit{NuSTAR} observations. Following an earlier work, we fit the spectra using a thermal Comptonization model with a relativistic…

High Energy Astrophysical Phenomena · Physics 2021-11-02 Samuzal Barua , V. Jithesh , Ranjeev Misra , Gulab C Dewangan , Rathin Sarma , Amit Pathak , Biman J Medhi

Due to their characteristic temperature and density, loop structures in active regions (ARs) can be seen bright in extreme ultraviolet (EUV) and soft X-ray images. The semiempirical determination of the three-dimensional (3D) distribution…

Solar and Stellar Astrophysics · Physics 2020-12-16 F. A. Nuevo , C. Mac Cormack , M. López Fuentes , A. M. Vásquez , C. H. Mandrini

We study the evolution of a small-scale emerging flux region (EFR) in the quiet Sun, from its emergence to its decay. We track processes and phenomena across all atmospheric layers, explore their interrelations and compare our findings with…

Solar and Stellar Astrophysics · Physics 2020-01-15 I. Kontogiannis , G. Tsiropoula , K. Tziotziou , C. Gontikakis , C. Kuckein , M. Verma , C. Denker

Coronal holes (CH) are regions of open magnetic field lines in the solar corona and the source of fast solar wind. Understanding the evolution of coronal holes is critical for solar magnetism as well as for accurate space weather forecasts.…

Space Physics · Physics 2018-05-02 Amr Hamada , Timo Asikainen , Ilpo Virtanen , Kalevi Mursula

We report measurements of a polar coronal hole during the recent solar minimum using the Extreme Ultraviolet Imaging Spectrometer on Hinode. Five observations are analyzed that span the polar coronal hole from the central meridian to the…

Solar and Stellar Astrophysics · Physics 2015-05-20 M. Hahn , P. Bryans , E. Landi , M. P. Miralles , D. W. Savin

The quiet solar corona consists of myriads of loop-like features, with magnetic fields originating from network and internetwork regions on the solar surface. The continuous interaction between these different magnetic patches leads to…

Solar and Stellar Astrophysics · Physics 2021-04-13 L. P. Chitta , H. Peter , P. R. Young

Coronal density, temperature and heat flux distributions for the equatorial and polar corona have been deduced by Lemaire [2012] from Saito's model of averaged coronal white light (WL) brightness and polarization observations. They are…

Solar and Stellar Astrophysics · Physics 2015-06-05 V. Pierrard , K. Borremans , J. F. Lemaire

We present a new diagnostic allowing one to measure the anisotropy of ion temperatures and non-thermal velocities as well as Doppler shifts with respect to the ambient magnetic field. This method provides new results, as well as independent…

Solar and Stellar Astrophysics · Physics 2015-06-12 M. Hahn , D. W. Savin
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