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Modeling Time-variable Elemental Abundances in Coronal Loop Simulations

delete2024-07-30
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OA
AI
J
Jeffrey W. Reep *
J
John Unverferth
W
Will Barnes
S
Sherry Chhabra
DOI:10.3847/2041-8213/ad64c3delete
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Abstract

Abstract

En 中文
Numerous recent X-ray observations of coronal loops in both active regions and solar flares have shown clearly that elemental abundances vary with time. Over the course of a flare, they have been found to move from coronal values toward photospheric values near the flare peak, before slowly returning to coronal values during the gradual phase. Coronal loop models typically assume that the elemental abundances are fixed, however. In this work, we introduce a time-variable abundance factor into the 0D ebtel++ code that models the changes due to chromospheric evaporation in order to understand how this affects coronal loop cooling. We find that for strong heating events (greater than or similar to 1 erg s-1 cm-3), the abundances quickly tend towards photospheric values. For smaller heating rates, the abundances fall somewhere between coronal and photospheric values, causing the loop to cool more quickly than the time-fixed photospheric cases (typical flare simulations) and more slowly than time-fixed coronal cases (typical AR simulations). This suggests heating rates in quiescent AR loops no larger than approximate to 0.1 erg s-1 cm-3 to be consistent with recent measurements of abundance factors f greater than or similar to 2.
Keywords:
SOLAR ACTIVE-REGION
NON-FLARING PLASMAS
CHROMOSPHERIC EVAPORATION
CHEMICAL-COMPOSITION
HEATING PROPERTIES
ATOMIC DATABASE
EVOLUTION
EMISSION
FLARES
REFLECTION

Journal

Astrophysical Journal Letters cover
Astrophysical Journal Letters
IF:
11.7
Papers:
1.2W
Citations:
5.9W

Organization

U
University of Hawaii Manoa
Scholars:
6.0K
Papers: 4.8K
Citations: 9
University of Hawaii System cover
University of Hawaii System
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1.6W
Papers: 1.5W
Citations: 1.2W
United States Department of Defense cover
United States Department of Defense
Scholars:
2.8W
Papers: 2.3W
Citations: 172
United States Naval Research Laboratory cover
United States Naval Research Laboratory
Scholars:
2.4K
Papers: 1.9K
Citations: 6.9K
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Cited Papers

Cited Papers

Simulating Solar Flare Irradiance with Multithreaded Models of Flare Arcades
err2020-05-21
err8
errOAAI
errReep, Jeffrey W.; Warren, Harry P.; Moore, Christopher S.; Suarez, Crisel; Hayes, Laura A.
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Highly efficient modeling of dynamic coronal loops
err2008-08-01
err270
PREAI
errKlimchuk, J. A.; Patsourakos, S.; Cargill, P. J.
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The Evolution of Plasma Composition during a Solar Flare
err2021-04-19
err15
errOAAI
errTo, Andy S. H.; Long, David M.; Baker, Deborah; Brooks, David H.; van Driel-Gesztelyi, Lidia; Laming, J. Martin; Valori, Gherardo
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Evolution of Elemental Abundances in Hot Active Region Cores from Chandrayaan-2 XSM Observations
err2023-09-27
err2
errOAAI
errMondal, Biswajit; Vadawale, Santosh V.; Del Zanna, Giulio; Mithun, N. P. S.; Sarkar, Aveek; Mason, Helen E.; Janardhan, P.; Bhardwaj, Anil
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