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Magnetic flux ropes are bundles of twisted magnetic field enveloping a central axis. They harbor free magnetic energy and can be progenitors of coronal mass ejections (CMEs), but identifying flux ropes on the Sun can be challenging. One of…

We present an X-ray spectral analysis of four solar analogs with different ages and magnetic activity levels. We find largely different coronal compositions. The most active stars tend to show an ``Inverse First Ionization Potential''…

Astrophysics · Physics 2007-05-23 M. Guedel , M. Audard , A. Sres , R. Wehrli , E. Behar , R. Mewe , A. J. J. Raassen , H. Magee

The Inverse First Ionization Potential (FIP) Effect, the depletion in coronal abundance of elements like Fe, Mg, and Si that are ionized in the solar chromosphere relative to those that are neutral, has been identified in several solar…

Solar and Stellar Astrophysics · Physics 2021-03-17 J. Martin Laming

The origin of the slow solar wind is still an open issue. It has been suggested that upflows at the edge of active regions (AR) can contribute to the slow solar wind. Here, we compared the upflow region and the AR core and studied how the…

Solar and Stellar Astrophysics · Physics 2021-08-04 Krzysztof Barczynski , Louise Harra , Lucia Kleint , Brandon Panos , David H. Brooks

Since the advent of X-ray and EUV spectroscopy, the discovery of the First Ionization Potential (FIP) effect--where coronal elemental compositions diverge from their photospheric values based on the element's FIP--has remained a key puzzle…

Solar and Stellar Astrophysics · Physics 2025-10-03 Biswajit Mondal , Amy R. Winebarger

Magnetic fields in the solar corona are responsible for a wide range of phenomena. However, any direct measurements of the coronal magnetic fields are very difficult due to lack of suitable spectral lines, weak magnetic fields, and high…

Solar and Stellar Astrophysics · Physics 2013-10-28 P. Vemareddy , A. Ambastha , T. Wiegelmann

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

One puzzling question in solar physics is the difference between elemental abundances in the photosphere and the corona. Elements with low first ionization potential (FIP) can be overabundant in the corona compared to the photosphere under…

Solar and Stellar Astrophysics · Physics 2019-06-05 Bálint Seli , Levente Kriskovics , Krisztián Vida

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

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

Magnetic flux ropes (FRs) are twisted structures appearing on the sun, predominantly in the magnetically concentrated regions. These structures appear as coronal features known as filaments or prominences in H$\alpha$ observations, and as…

Solar and Stellar Astrophysics · Physics 2024-10-04 P. Vemareddy

Context: Solar active regions (ARs) are key manifestations of the Sun's magnetic activity, displaying diverse spatial and temporal characteristics. Their formation and evolution play a crucial role in understanding the solar dynamo and…

Solar and Stellar Astrophysics · Physics 2025-08-06 M. Švanda , J. Jurčák , M. Schmassmann

The coronal magnetic field evolution of 20 bipolar active regions (ARs) is simulated from their emergence to decay using the time-dependent nonlinear force-free field method of Mackay et al. A time sequence of cleaned photospheric…

Solar and Stellar Astrophysics · Physics 2021-01-13 Stephanie L. Yardley , Duncan H. Mackay , Lucie M. Green

We revisit in more detail a model for element abundance fractionation in the solar chromosphere, that gives rise to the "FIP Effect" in the solar corona and wind. Elements with first ionization potential below about 10 eV, i.e. those that…

Solar and Stellar Astrophysics · Physics 2014-11-18 J. Martin Laming

The elemental composition in the coronae of low-activity solar-like stars appears to be related to fundamental stellar properties such as rotation, surface gravity, and spectral type. Here we use full-Sun observations from the Solar…

Solar and Stellar Astrophysics · Physics 2018-02-05 David H. Brooks , Deborah Baker , Lidia van Driel-Gesztelyi , Harry P. Warren

The elemental composition of the solar wind differs from the solar photospheric composition. Elements with low first ionization potential (FIP) appear enhanced compared to O in the solar wind relative to the respective photospheric…

Solar and Stellar Astrophysics · Physics 2018-11-14 Verena Heidrich-Meisner , Lars Berger , Robert F. Wimmer-Schweingruber

Elements with low First Ionization Potential (FIP) are known to be three to four times more abundant in active region loops of the solar corona than in the photosphere. There have been observations suggesting that this observed "FIP bias"…

In this study, we investigate the spatial distribution of highly varying plasma composition around one of the largest sunspots of solar cycle 24. Observations of the photosphere, chromosphere, and corona are brought together with magnetic…

Solar and Stellar Astrophysics · Physics 2021-01-27 D. Baker , M. Stangalini , G. Valori , D. H. Brooks , A. S. H. To , L. van Driel-Gesztelyi , P. Demoulin , D. Stansby , D. B. Jess , S. Jafarzadeh

Linking solar wind properties to the activities and characteristics of its source regions can enhance our understanding of its origin and generation mechanisms. Using the Mount Wilson magnetic classification (MWMC), we categorize all active…

Solar and Stellar Astrophysics · Physics 2025-10-13 Xinzheng Shi , Hui Fu , Zhenghua Huang , Limei Yan , Qi Liu , Lidong Xia

From a turbulent history, the study of abundances of elements in solar energetic particles (SEPs) has grown into an extensive field that probes the solar corona and the physical processes of SEP acceleration and transport. Underlying SEPs…

Solar and Stellar Astrophysics · Physics 2019-11-22 Donald V Reames