Source of the dayside cusp aurora
Monochromatic all‐sky imagers at South Pole and other Antarctic stations of the Automatic Geophysical Observatory chain recorded the aurora in the region where the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites crossed the dayside magnetopause. In several cas...
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ftpubmed:oai:pubmedcentral.nih.gov:5101848 2023-05-15T14:05:01+02:00 Source of the dayside cusp aurora Mende, S. B. Frey, H. U. Angelopoulos, V. 2016-08-22 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5101848/ https://doi.org/10.1002/2016JA022657 en eng John Wiley and Sons Inc. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5101848/ http://dx.doi.org/10.1002/2016JA022657 ©2016. The Authors. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs (http://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. CC-BY-NC-ND Research Articles Text 2016 ftpubmed https://doi.org/10.1002/2016JA022657 2016-11-20T01:11:49Z Monochromatic all‐sky imagers at South Pole and other Antarctic stations of the Automatic Geophysical Observatory chain recorded the aurora in the region where the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites crossed the dayside magnetopause. In several cases the magnetic field lines threading the satellites when mapped to the atmosphere were inside the imagers' field of view. From the THEMIS magnetic field and the plasma density measurements, we were able to locate the position of the magnetopause crossings and map it to the ionosphere using the Tsyganenko‐96 field model. Field line mapping is reasonably accurate on the dayside subsolar region where the field is strong, almost dipolar even though compressed. From these coordinated observations, we were able to prove that the dayside cusp aurora of high 630 nm brightness is on open field lines, and it is therefore direct precipitation from the magnetosheath. The cusp aurora contained significant highly structured N2 + 427.8 nm emission. The THEMIS measurements of the magnetosheath particle energy and density taken just outside the magnetopause compared to the intensity of the structured N2 + 427.8 nm emissions showed that the precipitating magnetosheath particles had to be accelerated. The most likely electron acceleration mechanism is by dispersive Alfvén waves propagating along the field line. Wave‐accelerated suprathermal electrons were seen by FAST and DMSP. The 427.8 nm wavelength channel also shows the presence of a lower latitude hard‐electron precipitation zone originating inside the magnetosphere. Text Antarc* Antarctic South pole South pole PubMed Central (PMC) Antarctic South Pole Journal of Geophysical Research: Space Physics 121 8 7728 7738 |
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Research Articles Mende, S. B. Frey, H. U. Angelopoulos, V. Source of the dayside cusp aurora |
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Monochromatic all‐sky imagers at South Pole and other Antarctic stations of the Automatic Geophysical Observatory chain recorded the aurora in the region where the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites crossed the dayside magnetopause. In several cases the magnetic field lines threading the satellites when mapped to the atmosphere were inside the imagers' field of view. From the THEMIS magnetic field and the plasma density measurements, we were able to locate the position of the magnetopause crossings and map it to the ionosphere using the Tsyganenko‐96 field model. Field line mapping is reasonably accurate on the dayside subsolar region where the field is strong, almost dipolar even though compressed. From these coordinated observations, we were able to prove that the dayside cusp aurora of high 630 nm brightness is on open field lines, and it is therefore direct precipitation from the magnetosheath. The cusp aurora contained significant highly structured N2 + 427.8 nm emission. The THEMIS measurements of the magnetosheath particle energy and density taken just outside the magnetopause compared to the intensity of the structured N2 + 427.8 nm emissions showed that the precipitating magnetosheath particles had to be accelerated. The most likely electron acceleration mechanism is by dispersive Alfvén waves propagating along the field line. Wave‐accelerated suprathermal electrons were seen by FAST and DMSP. The 427.8 nm wavelength channel also shows the presence of a lower latitude hard‐electron precipitation zone originating inside the magnetosphere. |
format |
Text |
author |
Mende, S. B. Frey, H. U. Angelopoulos, V. |
author_facet |
Mende, S. B. Frey, H. U. Angelopoulos, V. |
author_sort |
Mende, S. B. |
title |
Source of the dayside cusp aurora |
title_short |
Source of the dayside cusp aurora |
title_full |
Source of the dayside cusp aurora |
title_fullStr |
Source of the dayside cusp aurora |
title_full_unstemmed |
Source of the dayside cusp aurora |
title_sort |
source of the dayside cusp aurora |
publisher |
John Wiley and Sons Inc. |
publishDate |
2016 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5101848/ https://doi.org/10.1002/2016JA022657 |
geographic |
Antarctic South Pole |
geographic_facet |
Antarctic South Pole |
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Antarc* Antarctic South pole South pole |
genre_facet |
Antarc* Antarctic South pole South pole |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5101848/ http://dx.doi.org/10.1002/2016JA022657 |
op_rights |
©2016. The Authors. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs (http://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1002/2016JA022657 |
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Journal of Geophysical Research: Space Physics |
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121 |
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8 |
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7728 |
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7738 |
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