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The chemical composition of the solar corona is different from that of the solar photosphere, with the strongest variation being observed in active regions (ARs). Using data from the Extreme Ultraviolet (EUV) Imaging Spectrometer (EIS) on…

We use ACE/SWICS elemental composition data to compare the variations in solar wind fractionation as measured by SWICS during the last solar maximum (1999-2001), the solar minimum (2006-2009) and the period in which the Genesis spacecraft…

Solar and Stellar Astrophysics · Physics 2015-10-14 P. Pilleri , D. B. Reisenfeld , T. H. Zurbuchen , S. T. Lepri , P. Shearer , J. A. Gilbert , R. von Steiger , R. C. Wiens

The composition of the solar corona differs from that of the photosphere, with the plasma thought to fractionate in the solar chromosphere according to the First Ionisation Potential (FIP) of the different elements. This produces a FIP…

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

The ponderomotive force is suggested to be the main mechanism to produce the so-called first ionization potential (FIP) effect - the enrichment of low FIP elements observed in the outer solar atmosphere. It is well known that the ionization…

Solar and Stellar Astrophysics · Physics 2023-06-14 Juan Martínez-Sykora , Bart De Pontieu , Viggo H. Hansteen , Paola Testa , Q. M. Wargnier , Mikolaj Szydlarski

Elemental abundance effects in active coronae have eluded our understanding for almost three decades, since the discovery of the First Ionization Potential (FIP) effect on the sun. The goal of this paper is to monitor the same coronal…

Solar and Stellar Astrophysics · Physics 2012-12-04 Raanan Nordon , Ehud Behar , Stephen A. Drake

Main sequence stars of spectral types F, G, and K with low to moderate activity levels exhibit a recognizable pattern known as the first ionization potential effect (FIP effect), where elements with lower first ionization potentials are…

Solar and Stellar Astrophysics · Physics 2025-03-13 J. J. Chebly , K. Poppenhäger , J. D. Alvarado-Gómez , B. E. Wood

Element abundance ratios of magnesium to neon (Mg/Ne) and neon to oxygen (Ne/O) in the transition region of the quiet Sun have been derived by re-assessing previously published data from the Coronal Diagnostic Spectrometer on board the…

Solar and Stellar Astrophysics · Physics 2018-03-14 Peter R. Young

Solar coronal plasma composition is typically characterized by first ionization potential (FIP) bias. Using spectra obtained by Hinode's EUV Imaging Spectrometer (EIS) instrument, we present a series of large-scale, spatially resolved…

Solar and Stellar Astrophysics · Physics 2015-06-23 D. Baker , D. H. Brooks , P. Démoulin , S. L. Yardley , L. van Driel-Gesztelyi , D. M. Long , L. M. Green

Coronal elemental abundances are known to deviate from the photospheric values of their parent star, with the degree of deviation depending on the First Ionization Potential (FIP). This study focuses on the coronal composition of stars with…

Solar and Stellar Astrophysics · Physics 2015-05-13 Uria Peretz , Ehud Behar , Stephen A. Drake

This is a study of abundances of the elements He, C, N, O, Ne, Mg, Si, S, Ar, Ca, and Fe in solar energetic particles (SEPs) in the 2 - 15 MeV amu-1 region measured on the Wind spacecraft during 54 large SEP events occurring between…

Solar and Stellar Astrophysics · Physics 2015-06-16 Donald V. Reames

Solar flares exhibit complex variations in elemental abundances compared to photospheric values. We examine the spatial and temporal evolution of coronal abundances in the X8.2 flare on 2017 September 10, aiming to interpret the often…

Elemental abundance variations in the solar corona, commonly characterised by First Ionisation Potential (FIP) bias, provide crucial diagnostics of chromospheric processes. The ponderomotive force model, which attributes fractionation to…

Solar and Stellar Astrophysics · Physics 2026-04-16 Andy S. H. To , J. Martin Laming , Jeffrey Reep , Adam J. Finley

Elemental abundances provide a powerful diagnostic of the physical mechanisms and processes that heat the solar atmosphere and drive the solar wind. The First Ionisation Potential (FIP) effect and its inverse (IFIP) are observed both on the…

Solar and Stellar Astrophysics · Physics 2026-05-20 Stephanie L. Yardley

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 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

Sixty years ago the first observation was published showing solar energetic particles (SEPs) with a sampling of chemical elements. Thus began study of the direct products of dynamic physics in the solar corona. As we have progressed from…

Solar and Stellar Astrophysics · Physics 2021-08-19 Donald V. Reames

In this study, we employ the combined charged particle measurements from Integrated Science Investigation of the Sun (\ISOIS) onboard the Parker Solar Probe (PSP) and Energetic Particle Detector (EPD) onboard the Solar Orbiter (SolO) to…

The composition of plasma in the solar corona is characterised by the First Ionisation Potential (FIP) bias, and is thought to be the result of a ponderomotive force acting in the chromosphere to separate ionised from neutral plasma.…

Solar and Stellar Astrophysics · Physics 2026-03-06 Éabha Power , David M. Long , Teodora Mihailescu , Laura A. Hayes

Acceleration and transport of solar energetic particles (SEPs) causes their abundances, measured at constant velocity, to be enhanced or suppressed as a function of each ion's magnetic rigidity, and hence its atomic mass-to-charge ratio…

Solar and Stellar Astrophysics · Physics 2024-02-19 Donald V. Reames