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Energized Oxygen in the Magnetotail: Onset and Evolution of Magnetic Reconnection

Oxygen ions are a major constituent of magnetospheric plasma, yet the role of oxygen in processes such as magnetic reconnection continues to be poorly understood. Observations show that significant amounts of energized O(+) can be present in a magnetotail current sheet (CS). A population of thermal...

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Autores principales: George, Don E, Jahn, Jörg‐Micha
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9786576/
https://www.ncbi.nlm.nih.gov/pubmed/36582491
http://dx.doi.org/10.1029/2020JA028381
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author George, Don E
Jahn, Jörg‐Micha
author_facet George, Don E
Jahn, Jörg‐Micha
author_sort George, Don E
collection PubMed
description Oxygen ions are a major constituent of magnetospheric plasma, yet the role of oxygen in processes such as magnetic reconnection continues to be poorly understood. Observations show that significant amounts of energized O(+) can be present in a magnetotail current sheet (CS). A population of thermal O(+) only has a relatively minor effect on magnetic reconnection. Despite this, published studies have so far only concentrated on the role of the low‐energy thermal O(+). We present a study of magnetic reconnection in a thinning CS with energized O(+) present. Well‐established, three‐species, 2.5D particle‐in‐cell (PIC) kinetic simulations are used. Simulations of thermal H(+) and thermal O(+) validate our setup against published results. We then energize a thermal background O(+) based on published in situ measurements. A range of energization is applied to the background O(+). We discuss the effects of energized O(+) on CS thinning and the onset and evolution of magnetic reconnection. The presence of energized O(+) causes a two‐regime onset response in a thinning CS. As energization increases in the lower‐regime, reconnection develops at a single primary X‐line, increases time‐to‐onset, and suppresses the rate of evolution. As energization continues to increase in the higher‐regime, reconnection develops at multiple X‐lines, forming a stochastic plasmoid chain; decreases time‐to‐onset; and enhances evolution via a plasmoid instability. Energized O(+) drives a depletion of the background H(+) around the central CS. As the energization increases, the CS thinning begins to slow and eventually reverses.
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spelling pubmed-97865762022-12-27 Energized Oxygen in the Magnetotail: Onset and Evolution of Magnetic Reconnection George, Don E Jahn, Jörg‐Micha J Geophys Res Space Phys Research Article Oxygen ions are a major constituent of magnetospheric plasma, yet the role of oxygen in processes such as magnetic reconnection continues to be poorly understood. Observations show that significant amounts of energized O(+) can be present in a magnetotail current sheet (CS). A population of thermal O(+) only has a relatively minor effect on magnetic reconnection. Despite this, published studies have so far only concentrated on the role of the low‐energy thermal O(+). We present a study of magnetic reconnection in a thinning CS with energized O(+) present. Well‐established, three‐species, 2.5D particle‐in‐cell (PIC) kinetic simulations are used. Simulations of thermal H(+) and thermal O(+) validate our setup against published results. We then energize a thermal background O(+) based on published in situ measurements. A range of energization is applied to the background O(+). We discuss the effects of energized O(+) on CS thinning and the onset and evolution of magnetic reconnection. The presence of energized O(+) causes a two‐regime onset response in a thinning CS. As energization increases in the lower‐regime, reconnection develops at a single primary X‐line, increases time‐to‐onset, and suppresses the rate of evolution. As energization continues to increase in the higher‐regime, reconnection develops at multiple X‐lines, forming a stochastic plasmoid chain; decreases time‐to‐onset; and enhances evolution via a plasmoid instability. Energized O(+) drives a depletion of the background H(+) around the central CS. As the energization increases, the CS thinning begins to slow and eventually reverses. John Wiley and Sons Inc. 2022-09-26 2022-09 /pmc/articles/PMC9786576/ /pubmed/36582491 http://dx.doi.org/10.1029/2020JA028381 Text en ©2022. The Authors. https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
George, Don E
Jahn, Jörg‐Micha
Energized Oxygen in the Magnetotail: Onset and Evolution of Magnetic Reconnection
title Energized Oxygen in the Magnetotail: Onset and Evolution of Magnetic Reconnection
title_full Energized Oxygen in the Magnetotail: Onset and Evolution of Magnetic Reconnection
title_fullStr Energized Oxygen in the Magnetotail: Onset and Evolution of Magnetic Reconnection
title_full_unstemmed Energized Oxygen in the Magnetotail: Onset and Evolution of Magnetic Reconnection
title_short Energized Oxygen in the Magnetotail: Onset and Evolution of Magnetic Reconnection
title_sort energized oxygen in the magnetotail: onset and evolution of magnetic reconnection
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9786576/
https://www.ncbi.nlm.nih.gov/pubmed/36582491
http://dx.doi.org/10.1029/2020JA028381
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