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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 analyze Chandra X-ray spectra of the M0 V+M0 V binary GJ 338. As quantified by X-ray surface flux, these are the most inactive M dwarfs ever observed with X-ray grating spectroscopy. We focus on measuring coronal abundances, in…

Solar and Stellar Astrophysics · Physics 2015-06-05 Brian E. Wood , J. Martin Laming , Margarita Karovska

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

Sunspots are regions of decreased brightness on the visible surface of the Sun (photosphere) that are associated with strong magnetic fields. They have been found to be locations associated with solar flares, which occur when energy stored…

Solar and Stellar Astrophysics · Physics 2013-01-24 Sophie A. Murray

The large field-of-view of the Sun Watcher using Active Pixel System detector and Image Processing (SWAP) instrument on board the PRoject for Onboard Autonomy 2 (PROBA2) spacecraft provides a unique opportunity to study extended coronal…

Solar and Stellar Astrophysics · Physics 2020-08-05 Karen A. Meyer , Duncan H. Mackay , Dana-Camelia Talpeanu , Lisa A. Upton , Matthew J. West

Coronal dimmings are transient depletions of coronal plasma observed in extreme ultraviolet and soft X-rays, interpreted as low-corona signatures of coronal mass ejections (CMEs). Their evolution is closely linked to CME dynamics, flare…

Solar and Stellar Astrophysics · Physics 2026-03-26 Amaia Razquin , Karin Dissauer , Astrid M. Veronig , Graham Barnes

The solar atmosphere was traditionally represented with a simple one-dimensional model. Over the past few decades, this paradigm shifted for the chromosphere and corona that constitute the outer atmosphere, which is now considered a dynamic…

The observed solar activity is believed to be driven by the dissipation of nonpotential magnetic energy injected into the corona by dynamic processes in the photosphere. The enormous range of scales involved in the interaction makes it…

Solar and Stellar Astrophysics · Physics 2015-06-12 Vadim M. Uritsky , Joseph M. Davila , Leon Ofman , Aaron J. Coyner

Aims. This study investigates the magnetic evolution of solar active regions (ARs), with a particular focus on understanding how the magnetic morphology of simple and complex ARs changes throughout their lifetime. Methods. To analyse the…

Solar and Stellar Astrophysics · Physics 2025-05-29 Shabnam Nikbakhsh , Eija I. Tanskanen , Thomas Hackman

The origin of the slow solar wind is still an open issue. One possibility that has been suggested is that upflows at the edge of an active region can contribute to the slow solar wind. We aim to explain how the plasma upflows are generated,…

Intermediate stages between pores and sunspots are a rare phenomenon and can manifest with the formation of transient photospheric penumbral-like filaments. Although the magnetic field changes rapidly during the evolution of such filaments,…

Solar and Stellar Astrophysics · Physics 2023-05-10 Philip Lindner , Rolf Schlichenmaier , Nazaret Bello González , Jaime de la Cruz Rodríguez

We have performed 3D MHD simulations to study the effect of partial ionization in the process of magnetic flux emergence in the Sun. In fact, we continue previous work and we now focus: 1) on the emergence of the magnetic fields above the…

Solar and Stellar Astrophysics · Physics 2024-12-17 Georgios Chouliaras , V. Archontis

We use the first publically available data from the Daniel K. Inouye Solar Telescope (DKIST) to track magnetic connections from the solar photosphere into the corona. We scrutinize relationships between chromospheric magnetism and bright…

Solar and Stellar Astrophysics · Physics 2023-11-03 Philip Judge , Lucia Kleint , Roberto Casini , Alfred de Wijn , Tom Schad , Alexandra Tritschler

In this study we report detailed observations of magnetic environment at four footpoints of two warm coronal loops observed on 5 May 2016 in NOAA AR 12542 (Loop I) and 17 Dec 2015 in NOAA AR 12470 (Loop II). These loops were connecting a…

Solar and Stellar Astrophysics · Physics 2019-03-29 Seray Şahin , Vasyl Yurchyshyn , Pankaj Kumar , Ali Kilcik , Kwangsu Ahn , Xu Yang

We use coronal imaging observations with SDO/AIA, and Hinode/EIS spectral data, to explore the potential of narrow band EUV imaging data for diagnosing the presence of hot (T >~5MK) coronal plasma in active regions. We analyze observations…

Solar and Stellar Astrophysics · Physics 2015-06-04 Paola Testa , Fabio Reale

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

Coronal upflows at the edges of active regions (AR), which are a possible source of slow solar wind, have been found to connect with dynamics in the transition region. To infer at what scale transition region dynamics connect to AR upflows,…

Solar and Stellar Astrophysics · Physics 2021-09-08 Zhenghua Huang , Lidong Xia , Hui Fu , Zhenyong Hou , Ziyuan Wang

Recent advances in observational performance and numerical simulations have revolutionised our understanding of the solar chromosphere. This concerns in particular the structure and dynamics on small spatial and temporal scales. As a…

Solar and Stellar Astrophysics · Physics 2009-12-01 Sven Wedemeyer-Böhm

The young active star AB Dor (K1 IV-V) has been observed 16 times in the last three years with the XMM-Newton and Chandra observatories, totalling 650 ks of high-resolution X-ray spectra. The XMM/RGS observations with the highest and lowest…

Astrophysics · Physics 2009-11-10 J. Sanz-Forcada , A. Maggio , G. Micela

We investigate the morphology and temporal variability of a quiet Sun network region in different solar layers. The emission in several EUV spectral lines through both raster and slot time series, recorded by EIS/Hinode is studied along…

Solar and Stellar Astrophysics · Physics 2018-03-26 Ioannis Kontogiannis , Costis Gontikakis , Georgia Tsiropoula , Kostas Tziotziou
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