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Solar atmospheric elemental abundances are now known to vary both in space and time. Dynamic modeling of these changes is therefore necessary to improve the accuracy of radiative hydrodynamic simulations. Recent studies have shown that…

Solar and Stellar Astrophysics · Physics 2026-02-13 David H. Brooks , Jeffrey W. Reep , Andy S. H. To , Luke Fushimi Benavitz , Lucas A. Tarr

We present an analysis of the first connection mosaic made by the SPICE instrument on board of the ESA / NASA Solar Orbiter mission on March 2nd, 2022. The data will be used to map coronal composition that will be compared with in-situ…

Using multiwavelength imaging observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) on 03 May 2012, we present a novel physical scenario for the formation of a temporary X-point in the solar…

Solar and Stellar Astrophysics · Physics 2020-01-08 A. K. Srivastava , Sudheer K. Mishra , P. Jelínek , Tanmoy Samanta , Hui Tian , Vaibhav Pant , P. Kayshap , D. Banerjee , J. G. Doyle , B. N. Dwivedi

Aims: Changes of the magnetic field and the line-of-sight velocities in the photosphere are being reported for an M-class flare that originated at a $\delta$-spot belonging to active region NOAA 11865. Methods: High-resolution ground-based…

We discuss the evolution of solar coronal element abundances over an active region lifetime. Magneto-convection drives the complexity of magnetic fields that emerge above the photosphere. This complexity is dissipated, together with that of…

Solar and Stellar Astrophysics · Physics 2025-12-16 David H. Brooks , Deborah Baker , David M. Long. Paola Testa , Harry P. Warren

High-resolution spectropolarimetry has opened new avenues for understanding how chromospheric waves shape coronal plasma composition. All modeling efforts so far highlight wave activity and, in particular, the ponderomotive force associated…

Solar and Stellar Astrophysics · Physics 2026-05-14 M. Murabito , M. Stangalini

Many jets are detected at X-ray wavelengths in the Sun's polar regions, and the ejected plasma along the jets has been suggested to contribute mass to the fast solar wind. From in-situ measurements in the magnetosphere, it has been found…

Solar and Stellar Astrophysics · Physics 2015-08-19 Kyoung-Sun Lee , David H. Brooks , Shinsuke Imada

Why the tenuous solar outer atmosphere, or corona, is much hotter than the underlying layers remains one of the greatest challenge for solar modeling. Detailed diagnostics of the coronal thermal structure come from extreme ultraviolet (EUV)…

Solar and Stellar Astrophysics · Physics 2018-05-02 Gregory Fleishman , Sophie Musset , Véronique Bommier , Lindsay Glesener

Plasma composition measurements are a vital tool for the success of current and future solar missions, but density and temperature insensitive spectroscopic diagnostic ratios are sparse, and their underlying accuracy in determining the…

Solar and Stellar Astrophysics · Physics 2024-10-22 David H. Brooks , Harry P. Warren , Deborah Baker , Sarah A. Matthews , Stephanie L. Yardley

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 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

Accurate forecasting of space weather requires knowledge of the source regions where solar energetic particles (SEP) and eruptive events originate. Recent work has linked several major SEP events in 2014, January, to specific features in…

Solar and Stellar Astrophysics · Physics 2021-09-24 David H. Brooks , Stephanie L. Yardley

We report X-ray spectroscopic results for four giant solar flares occurred on 2005 September 7 (X17.0), 2005 September 8 (X5.4), 2005 September 9 (X6.2), and 2006 December 5 (X9.0), obtained from Earth albedo data with the X-ray imaging…

We have performed 3-D numerical simulations to investigate the effect of partial ionization on the process of magnetic flux emergence. In our study, we have modified the single-fluid MHD equations to include the presence of neutrals and…

Solar and Stellar Astrophysics · Physics 2023-07-26 Georgios Chouliaras , P. Syntelis , V. Archontis

The solar active region NOAA 11719 produced a large two-ribbon flare on 11 April 2013. We have investigated the sudden variations in the photospheric magnetic fields in this active region during the flare employing the magnetograms obtained…

Solar and Stellar Astrophysics · Physics 2016-10-27 Brajesh Kumar , A. Raja Bayanna , P. Venkatakrishnan , Shibu K. Mathew

The elemental composition of the Sun's hot atmosphere, the corona, shows a distinctive pattern that is different than the underlying surface, or photosphere (Pottasch 1963). Elements that are easy to ionize in the chromosphere are enhanced…

Solar and Stellar Astrophysics · Physics 2022-05-18 David H. Brooks , Deborah Baker , Lidia van Driel-Gesztelyi , Harry P. Warren , Stephanie L. Yardley

We present measurements of relative elemental abundances in plumes and interplumes. Plumes are bright, narrow structures in coronal holes that extend along open magnetic field lines far out into the corona. Previous work has found that in…

Solar and Stellar Astrophysics · Physics 2015-07-15 Chloé Guennou , Michael Hahn , Daniel Wolf Savin

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

In the present work, we analyze a filament eruption associated with an ICME that arrived at L1 on August 5th, 2011. In multi-wavelength SDO/AIA images, three plasma parcels within the filament were tracked at high-cadence along the solar…

Solar and Stellar Astrophysics · Physics 2018-06-27 Manan Kocher , Enrico Landi , Susan T. Lepri

Quasi-periodic pulsations (QPP) are usually found in the light curves of solar and stellar flares, they carry the features of time characteristics and plasma emission of the flaring core, and could be used to diagnose the coronas of the Sun…

Solar and Stellar Astrophysics · Physics 2020-01-08 Ding Yuan , Song Feng , Dong Li , Zhongjun Ning , Baolin Tan