3D GUMICS simulations of northward IMF magnetotail structure
3D GUMICS simulations of northward IMF magnetotail structure
This study presents a re-evaluation of the Kullen and Janhunen (2004, https://doi.org/10.5194/angeo-22-951-2004) global northward interplanetary magnetic field (IMF) simulation, using the Grand Unified Magnetosphere–Ionosphere Coupling Simulation version 4 (GUMICS-4), a global MHD model. We investigate the dynamic coupling between northward IMF conditions and the Earth’s magnetotail and compare the results to observation-based mechanisms for the formation of transpolar arcs. The results of this study reveal that under northward IMF conditions (and northward IMF initialization), a large closed field line region forms in the magnetotail, with similarities to transpolar arc structures observed from spacecraft data. This interpretation is supported by the simultaneous increase of closed flux measured in the magnetotail. However, the reconnection configuration differs in several respects from previously theorized magnetotail structures that have been inferred from both observations and simulations results and associated with transpolar arcs. We observe that dawn–dusk lobe regions form as a result of high-latitude reconnection during the initialization stages, which later come into contact as the change in the IMF B y component causes the magnetotail to twist. We conclude that in the GUMICS simulation, transpolar arc-like structures are formed as a result of reconnection in the magnetotail, rather than high-latitude reconnection or due to the mapping of the plasma sheet through a twisted magnetotail as interpreted from previous analysis of GUMICS simulations.
MHD simulation, magnetotail reconnection, northward IMF, transpolar arc
Fryer, L.J.
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Fear, R.C.
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Gingell, I.L.
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Coxon, J.C.
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Palmroth, M.
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Hoilijoki, S.
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Janhunen, P.
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Kullen, A.
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Cassak, P.A.
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11 August 2023
Fryer, L.J.
6a9fd678-d71b-4352-a74f-51fa0bdc4542
Fear, R.C.
8755b9ed-c7dc-4cbb-ac9b-56235a0431ab
Gingell, I.L.
ba7b8113-3833-40d8-a879-aab3f987455d
Coxon, J.C.
566baea5-6a30-4855-bde3-a09c115efde4
Palmroth, M.
8a0f55b3-8eed-43b1-97dc-60b8b26e058d
Hoilijoki, S.
f04ec08e-8b58-4cde-8516-810d8627464d
Janhunen, P.
42ed78b6-99a9-4d68-8192-14d98da6bd64
Kullen, A.
9575b1dc-27c9-4367-b77a-045c1746ae39
Cassak, P.A.
7741c6ca-3f6d-4afa-90a8-0b022b519b6d
Fryer, L.J., Fear, R.C., Gingell, I.L., Coxon, J.C., Palmroth, M., Hoilijoki, S., Janhunen, P., Kullen, A. and Cassak, P.A.
(2023)
3D GUMICS simulations of northward IMF magnetotail structure.
Journal of Geophysical Research: Space Physics, 128 (8), [e2023JA031317].
(doi:10.1029/2023JA031317).
Abstract
This study presents a re-evaluation of the Kullen and Janhunen (2004, https://doi.org/10.5194/angeo-22-951-2004) global northward interplanetary magnetic field (IMF) simulation, using the Grand Unified Magnetosphere–Ionosphere Coupling Simulation version 4 (GUMICS-4), a global MHD model. We investigate the dynamic coupling between northward IMF conditions and the Earth’s magnetotail and compare the results to observation-based mechanisms for the formation of transpolar arcs. The results of this study reveal that under northward IMF conditions (and northward IMF initialization), a large closed field line region forms in the magnetotail, with similarities to transpolar arc structures observed from spacecraft data. This interpretation is supported by the simultaneous increase of closed flux measured in the magnetotail. However, the reconnection configuration differs in several respects from previously theorized magnetotail structures that have been inferred from both observations and simulations results and associated with transpolar arcs. We observe that dawn–dusk lobe regions form as a result of high-latitude reconnection during the initialization stages, which later come into contact as the change in the IMF B y component causes the magnetotail to twist. We conclude that in the GUMICS simulation, transpolar arc-like structures are formed as a result of reconnection in the magnetotail, rather than high-latitude reconnection or due to the mapping of the plasma sheet through a twisted magnetotail as interpreted from previous analysis of GUMICS simulations.
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JGR Space Physics - 2023 - Fryer
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Accepted/In Press date: 17 July 2023
e-pub ahead of print date: 27 July 2023
Published date: 11 August 2023
Additional Information:
Funding Information:
LJF is supported by the UK’s Science and Technology Facilities Council (STFC) through studentship ST/T506424/1 (2279917). RCF is supported by STFC consolidated Grant ST/R000719/1. MP is supported by the Academy of Finland Grants 339327, 335554, 347795, 345701, and 336805. PAC is supported by NASA Grant 80NSSC22K0323.
Publisher Copyright:
©2023. The Authors.
Keywords:
MHD simulation, magnetotail reconnection, northward IMF, transpolar arc
Identifiers
Local EPrints ID: 482082
URI: http://eprints.soton.ac.uk/id/eprint/482082
ISSN: 2169-9380
PURE UUID: 9298fd6f-8327-4242-9f82-b0a6a2f08dd8
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Date deposited: 19 Sep 2023 16:31
Last modified: 18 Mar 2024 03:55
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Contributors
Author:
M. Palmroth
Author:
S. Hoilijoki
Author:
P. Janhunen
Author:
A. Kullen
Author:
P.A. Cassak
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