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Main Authors: Orlovskij, Dominik, To, Andy S. H., Long, David M.
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.25325
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author Orlovskij, Dominik
To, Andy S. H.
Long, David M.
author_facet Orlovskij, Dominik
To, Andy S. H.
Long, David M.
contents Sulphur, with a first ionisation potential (FIP) of 10.36 eV, lies at the boundary between low- and high-FIP elements, making it particularly sensitive to fractionation processes in the solar atmosphere. Sulphur exhibits variable behaviour across solar environments, with coronal remote sensing studies often observing it as a high-FIP element while in-situ measurements sometimes detect low-FIP-like enhancement. Sulphur also exhibits variable behaviour during flares and magnetic restructuring. To understand sulphur's variations, we quantify how sulphur's FIP bias depends on potential field source surface (PFSS)-derived loop properties. We analyse nine Hinode/EUV Imaging Spectrometer (EIS) raster observations using four diagnostic line pairs (Si X 258.37 A / S X 264.23 A, S XI 188.68 A / Ar XI 188.81 A, Ca XIV 193.87 A / Ar XIV 194.40 A, and Fe XVI 262.98 A / S XIII 256.69 A), with FIP biases derived using differential emission measures (DEM) calculated via regularised inversion. Our results show that abundances of low-FIP elements, including sulphur, decrease above approximately 150 G relative to the high-FIP element Ar, while showing no dependence on loop length. This provides evidence that FIP fractionation is modulated by mean magnetic field strength of coronal loops.
format Preprint
id arxiv_https___arxiv_org_abs_2605_25325
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Signs of Sulphur fractionation under high magnetic field strength
Orlovskij, Dominik
To, Andy S. H.
Long, David M.
Solar and Stellar Astrophysics
Sulphur, with a first ionisation potential (FIP) of 10.36 eV, lies at the boundary between low- and high-FIP elements, making it particularly sensitive to fractionation processes in the solar atmosphere. Sulphur exhibits variable behaviour across solar environments, with coronal remote sensing studies often observing it as a high-FIP element while in-situ measurements sometimes detect low-FIP-like enhancement. Sulphur also exhibits variable behaviour during flares and magnetic restructuring. To understand sulphur's variations, we quantify how sulphur's FIP bias depends on potential field source surface (PFSS)-derived loop properties. We analyse nine Hinode/EUV Imaging Spectrometer (EIS) raster observations using four diagnostic line pairs (Si X 258.37 A / S X 264.23 A, S XI 188.68 A / Ar XI 188.81 A, Ca XIV 193.87 A / Ar XIV 194.40 A, and Fe XVI 262.98 A / S XIII 256.69 A), with FIP biases derived using differential emission measures (DEM) calculated via regularised inversion. Our results show that abundances of low-FIP elements, including sulphur, decrease above approximately 150 G relative to the high-FIP element Ar, while showing no dependence on loop length. This provides evidence that FIP fractionation is modulated by mean magnetic field strength of coronal loops.
title Signs of Sulphur fractionation under high magnetic field strength
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2605.25325