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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ftcdlib:oai:escholarship.org/ark:/13030/qt9qs6d3vf 2023-05-15T13:32:36+02:00 Source of the dayside cusp aurora. Mende, SB Frey, HU Angelopoulos, V 7728 - 7738 2016-08-22 application/pdf https://escholarship.org/uc/item/9qs6d3vf unknown eScholarship, University of California qt9qs6d3vf https://escholarship.org/uc/item/9qs6d3vf public Journal of geophysical research. Space physics, vol 121, iss 8 cusp aurora Astronomical and Space Sciences Atmospheric Sciences article 2016 ftcdlib 2021-01-24T17:37:54Z 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. Article in Journal/Newspaper Antarc* Antarctic South pole South pole University of California: eScholarship Antarctic South Pole |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
cusp aurora Astronomical and Space Sciences Atmospheric Sciences |
spellingShingle |
cusp aurora Astronomical and Space Sciences Atmospheric Sciences Mende, SB Frey, HU Angelopoulos, V Source of the dayside cusp aurora. |
topic_facet |
cusp aurora Astronomical and Space Sciences Atmospheric Sciences |
description |
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 |
Article in Journal/Newspaper |
author |
Mende, SB Frey, HU Angelopoulos, V |
author_facet |
Mende, SB Frey, HU Angelopoulos, V |
author_sort |
Mende, SB |
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 |
eScholarship, University of California |
publishDate |
2016 |
url |
https://escholarship.org/uc/item/9qs6d3vf |
op_coverage |
7728 - 7738 |
geographic |
Antarctic South Pole |
geographic_facet |
Antarctic South Pole |
genre |
Antarc* Antarctic South pole South pole |
genre_facet |
Antarc* Antarctic South pole South pole |
op_source |
Journal of geophysical research. Space physics, vol 121, iss 8 |
op_relation |
qt9qs6d3vf https://escholarship.org/uc/item/9qs6d3vf |
op_rights |
public |
_version_ |
1766028577902428160 |