North-South Asymmetry in the Geographic Location of Auroral Substorms correlated with Ionospheric Effects
Energetic particles of magnetospheric origin constantly strike the Earth’s upper atmosphere in the polar regions, producing optical emissions known as the aurora. The most spectacular auroral displays are associated with recurrent events called magnetospheric substorms (aka auroral substorms). Subst...
Published in: | Scientific Reports |
---|---|
Main Authors: | , , |
Format: | Text |
Language: | English |
Published: |
Nature Publishing Group UK
2018
|
Subjects: | |
Online Access: | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6250675/ http://www.ncbi.nlm.nih.gov/pubmed/30467409 https://doi.org/10.1038/s41598-018-35091-2 |
id |
ftpubmed:oai:pubmedcentral.nih.gov:6250675 |
---|---|
record_format |
openpolar |
spelling |
ftpubmed:oai:pubmedcentral.nih.gov:6250675 2023-05-15T13:55:36+02:00 North-South Asymmetry in the Geographic Location of Auroral Substorms correlated with Ionospheric Effects Liou, Kan Sotirelis, Thomas Mitchell, Elizabeth J. 2018-11-22 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6250675/ http://www.ncbi.nlm.nih.gov/pubmed/30467409 https://doi.org/10.1038/s41598-018-35091-2 en eng Nature Publishing Group UK http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6250675/ http://www.ncbi.nlm.nih.gov/pubmed/30467409 http://dx.doi.org/10.1038/s41598-018-35091-2 © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. CC-BY Article Text 2018 ftpubmed https://doi.org/10.1038/s41598-018-35091-2 2018-12-02T02:04:29Z Energetic particles of magnetospheric origin constantly strike the Earth’s upper atmosphere in the polar regions, producing optical emissions known as the aurora. The most spectacular auroral displays are associated with recurrent events called magnetospheric substorms (aka auroral substorms). Substorms are initiated in the nightside magnetosphere on closed magnetic field lines. As a consequence, it is generally thought that auroral substorms should occur in both hemispheres on the same field line (i.e., magnetically conjugated). However, such a hypothesis has not been verified statistically. Here, by analyzing 2659 auroral substorms acquired by the Ultraviolet Imager on board the NASA satellite “Polar”, we have discovered surprising evidence that the averaged location for substorm onsets is not conjugate but shows a geographic preference that cannot be easily explained by current substorm theories. In the Northern Hemisphere (NH) the auroral substorms occur most frequently in Churchill, Canada (~90°W) and Khatanga, Siberia (~100°E), up to three times as often as in Iceland (~22°W). In the Southern Hemisphere (SH), substorms occur more frequently over a location in the Antarctic ocean (~120°E), up to ~4 times more than over the Antarctic Continent. Such a large difference in the longitudinal distribution of north and south onset defies the common belief that substorms in the NH and SH should be magnetically conjugated. A further analysis indicates that these substorm events occurred more frequently when more of the ionosphere was dark. These geographic areas also coincide with regions where the Earth’s magnetic field is largest. These facts suggest that auroral substorms occur more frequently, and perhaps more intensely, when the ionospheric conductivity is lower. With much of the magnetotail energy coming from the solar wind through merging of the interplanetary and Earth’s magnetic field, it is generally thought that the occurrence of substorms is externally controlled by the solar wind and plasma instability ... Text Antarc* Antarctic Antarctic Ocean Iceland khatanga Siberia PubMed Central (PMC) Antarctic Antarctic Ocean Canada The Antarctic Scientific Reports 8 1 |
institution |
Open Polar |
collection |
PubMed Central (PMC) |
op_collection_id |
ftpubmed |
language |
English |
topic |
Article |
spellingShingle |
Article Liou, Kan Sotirelis, Thomas Mitchell, Elizabeth J. North-South Asymmetry in the Geographic Location of Auroral Substorms correlated with Ionospheric Effects |
topic_facet |
Article |
description |
Energetic particles of magnetospheric origin constantly strike the Earth’s upper atmosphere in the polar regions, producing optical emissions known as the aurora. The most spectacular auroral displays are associated with recurrent events called magnetospheric substorms (aka auroral substorms). Substorms are initiated in the nightside magnetosphere on closed magnetic field lines. As a consequence, it is generally thought that auroral substorms should occur in both hemispheres on the same field line (i.e., magnetically conjugated). However, such a hypothesis has not been verified statistically. Here, by analyzing 2659 auroral substorms acquired by the Ultraviolet Imager on board the NASA satellite “Polar”, we have discovered surprising evidence that the averaged location for substorm onsets is not conjugate but shows a geographic preference that cannot be easily explained by current substorm theories. In the Northern Hemisphere (NH) the auroral substorms occur most frequently in Churchill, Canada (~90°W) and Khatanga, Siberia (~100°E), up to three times as often as in Iceland (~22°W). In the Southern Hemisphere (SH), substorms occur more frequently over a location in the Antarctic ocean (~120°E), up to ~4 times more than over the Antarctic Continent. Such a large difference in the longitudinal distribution of north and south onset defies the common belief that substorms in the NH and SH should be magnetically conjugated. A further analysis indicates that these substorm events occurred more frequently when more of the ionosphere was dark. These geographic areas also coincide with regions where the Earth’s magnetic field is largest. These facts suggest that auroral substorms occur more frequently, and perhaps more intensely, when the ionospheric conductivity is lower. With much of the magnetotail energy coming from the solar wind through merging of the interplanetary and Earth’s magnetic field, it is generally thought that the occurrence of substorms is externally controlled by the solar wind and plasma instability ... |
format |
Text |
author |
Liou, Kan Sotirelis, Thomas Mitchell, Elizabeth J. |
author_facet |
Liou, Kan Sotirelis, Thomas Mitchell, Elizabeth J. |
author_sort |
Liou, Kan |
title |
North-South Asymmetry in the Geographic Location of Auroral Substorms correlated with Ionospheric Effects |
title_short |
North-South Asymmetry in the Geographic Location of Auroral Substorms correlated with Ionospheric Effects |
title_full |
North-South Asymmetry in the Geographic Location of Auroral Substorms correlated with Ionospheric Effects |
title_fullStr |
North-South Asymmetry in the Geographic Location of Auroral Substorms correlated with Ionospheric Effects |
title_full_unstemmed |
North-South Asymmetry in the Geographic Location of Auroral Substorms correlated with Ionospheric Effects |
title_sort |
north-south asymmetry in the geographic location of auroral substorms correlated with ionospheric effects |
publisher |
Nature Publishing Group UK |
publishDate |
2018 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6250675/ http://www.ncbi.nlm.nih.gov/pubmed/30467409 https://doi.org/10.1038/s41598-018-35091-2 |
geographic |
Antarctic Antarctic Ocean Canada The Antarctic |
geographic_facet |
Antarctic Antarctic Ocean Canada The Antarctic |
genre |
Antarc* Antarctic Antarctic Ocean Iceland khatanga Siberia |
genre_facet |
Antarc* Antarctic Antarctic Ocean Iceland khatanga Siberia |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6250675/ http://www.ncbi.nlm.nih.gov/pubmed/30467409 http://dx.doi.org/10.1038/s41598-018-35091-2 |
op_rights |
© The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1038/s41598-018-35091-2 |
container_title |
Scientific Reports |
container_volume |
8 |
container_issue |
1 |
_version_ |
1766262361248759808 |