Conjugate observation of auroral finger-like structures by ground-based all-sky cameras and THEMIS satellites
In this study, we analyze the first conjugate observation of auroral finger-like structures using ground-based all-sky cameras and the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites and investigated associated physical processes that are a cause of auroral fr...
Published in: | Journal of Geophysical Research: Space Physics |
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American Geophysical Union
2017
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Online Access: | http://hdl.handle.net/2237/27068 https://doi.org/10.1002/2016JA023774 https://nagoya.repo.nii.ac.jp/record/24848/files/Nishi_et_al-2017-Journal_of_Geophysical_Research-_Space_Physics.pdf |
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ftnagoyauniv:oai:nagoya.repo.nii.ac.jp:00024848 2024-06-09T07:46:27+00:00 Conjugate observation of auroral finger-like structures by ground-based all-sky cameras and THEMIS satellites Katsuki, Nishi 73892 Kazuo, Shiokawa 73893 Dennis, Frühauf 73894 2017-07 application/pdf http://hdl.handle.net/2237/27068 https://doi.org/10.1002/2016JA023774 https://nagoya.repo.nii.ac.jp/record/24848/files/Nishi_et_al-2017-Journal_of_Geophysical_Research-_Space_Physics.pdf eng eng American Geophysical Union https://doi.org/10.1002/2016JA023774 Journal of Geophysical Research-Space Physics 7 122 7291 7306 http://doi.org/10.1002/2016JA023774 http://hdl.handle.net/2237/27068 2169-9402 https://nagoya.repo.nii.ac.jp/record/24848/files/Nishi_et_al-2017-Journal_of_Geophysical_Research-_Space_Physics.pdf © 2017 American Geophysical Union 2017 ftnagoyauniv https://doi.org/10.1002/2016JA023774 2024-05-15T13:20:52Z In this study, we analyze the first conjugate observation of auroral finger-like structures using ground-based all-sky cameras and the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites and investigated associated physical processes that are a cause of auroral fragmentation into patches. Two events are reported: one is a conjugate event, and the other is a nearly conjugate event. The conjugate event was observed at Narsarsuaq (magnetic latitude: 65.3°N), Greenland, at 0720–0820 UT (0506–0606 LT) on 17 February 2012. Analysis of the event revealed the following observational facts: (1) variation of parallel electron energy fluxes observed by THEMIS-E shows a correspondence to the auroral intensity variation, (2) plasma pressure and magnetic pressure fluctuate in antiphase with time scales of 5–20 min, and (3) perpendicular ion velocity is very small (less than 50 km/s). In the latter event, observed at Gakona, Alaska, on 2 February 2008, the THEMIS-D satellite passed across higher latitudes of finger-like structures. The data from THEMIS-D also showed the antiphase fluctuation between plasma pressure and magnetic pressure and the small perpendicular ion velocity. From these observations, we suggest that the finger-like structures are caused by a pressure-driven instability in the balance of plasma and magnetic pressures in the magnetosphere. journal article Other/Unknown Material Greenland Narsarsuaq Alaska Nagoya University: NAGOYA Repository Greenland Journal of Geophysical Research: Space Physics 122 7 7291 7306 |
institution |
Open Polar |
collection |
Nagoya University: NAGOYA Repository |
op_collection_id |
ftnagoyauniv |
language |
English |
description |
In this study, we analyze the first conjugate observation of auroral finger-like structures using ground-based all-sky cameras and the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites and investigated associated physical processes that are a cause of auroral fragmentation into patches. Two events are reported: one is a conjugate event, and the other is a nearly conjugate event. The conjugate event was observed at Narsarsuaq (magnetic latitude: 65.3°N), Greenland, at 0720–0820 UT (0506–0606 LT) on 17 February 2012. Analysis of the event revealed the following observational facts: (1) variation of parallel electron energy fluxes observed by THEMIS-E shows a correspondence to the auroral intensity variation, (2) plasma pressure and magnetic pressure fluctuate in antiphase with time scales of 5–20 min, and (3) perpendicular ion velocity is very small (less than 50 km/s). In the latter event, observed at Gakona, Alaska, on 2 February 2008, the THEMIS-D satellite passed across higher latitudes of finger-like structures. The data from THEMIS-D also showed the antiphase fluctuation between plasma pressure and magnetic pressure and the small perpendicular ion velocity. From these observations, we suggest that the finger-like structures are caused by a pressure-driven instability in the balance of plasma and magnetic pressures in the magnetosphere. journal article |
author |
Katsuki, Nishi 73892 Kazuo, Shiokawa 73893 Dennis, Frühauf 73894 |
spellingShingle |
Katsuki, Nishi 73892 Kazuo, Shiokawa 73893 Dennis, Frühauf 73894 Conjugate observation of auroral finger-like structures by ground-based all-sky cameras and THEMIS satellites |
author_facet |
Katsuki, Nishi 73892 Kazuo, Shiokawa 73893 Dennis, Frühauf 73894 |
author_sort |
Katsuki, Nishi |
title |
Conjugate observation of auroral finger-like structures by ground-based all-sky cameras and THEMIS satellites |
title_short |
Conjugate observation of auroral finger-like structures by ground-based all-sky cameras and THEMIS satellites |
title_full |
Conjugate observation of auroral finger-like structures by ground-based all-sky cameras and THEMIS satellites |
title_fullStr |
Conjugate observation of auroral finger-like structures by ground-based all-sky cameras and THEMIS satellites |
title_full_unstemmed |
Conjugate observation of auroral finger-like structures by ground-based all-sky cameras and THEMIS satellites |
title_sort |
conjugate observation of auroral finger-like structures by ground-based all-sky cameras and themis satellites |
publisher |
American Geophysical Union |
publishDate |
2017 |
url |
http://hdl.handle.net/2237/27068 https://doi.org/10.1002/2016JA023774 https://nagoya.repo.nii.ac.jp/record/24848/files/Nishi_et_al-2017-Journal_of_Geophysical_Research-_Space_Physics.pdf |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Narsarsuaq Alaska |
genre_facet |
Greenland Narsarsuaq Alaska |
op_relation |
https://doi.org/10.1002/2016JA023774 Journal of Geophysical Research-Space Physics 7 122 7291 7306 http://doi.org/10.1002/2016JA023774 http://hdl.handle.net/2237/27068 2169-9402 https://nagoya.repo.nii.ac.jp/record/24848/files/Nishi_et_al-2017-Journal_of_Geophysical_Research-_Space_Physics.pdf |
op_rights |
© 2017 American Geophysical Union |
op_doi |
https://doi.org/10.1002/2016JA023774 |
container_title |
Journal of Geophysical Research: Space Physics |
container_volume |
122 |
container_issue |
7 |
container_start_page |
7291 |
op_container_end_page |
7306 |
_version_ |
1801376302451654656 |