Average field-aligned ion velocity over the EISCAT radars
Long-term measurements by the European Incoherent Scatter (EISCAT) radars at Tromsø (69.6° N, 19.2° E) and Svalbard (78.2° N, 16.0° E) are used to determine the climatology of the field-aligned ion velocity in the F-region ionosphere (175–475 km) at high latitudes. The average ion velocity is calcul...
Published in: | Journal of Geophysical Research: Space Physics |
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Language: | English |
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2019
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Online Access: | https://eprints.lancs.ac.uk/id/eprint/86240/ https://eprints.lancs.ac.uk/id/eprint/86240/1/EISCAT_Vi_accepted_article.pdf https://eprints.lancs.ac.uk/id/eprint/86240/4/Yamazaki_et_al_2017_Journal_of_Geophysical_Research_Space_Physics.pdf https://doi.org/10.1002/2017JA023974 |
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ftulancaster:oai:eprints.lancs.ac.uk:86240 2023-08-27T04:09:13+02:00 Average field-aligned ion velocity over the EISCAT radars Yamazaki, Yosuke Kosch, Michael Jurgen Ogawa, Yasunobu 2019-05-31 application/pdf https://eprints.lancs.ac.uk/id/eprint/86240/ https://eprints.lancs.ac.uk/id/eprint/86240/1/EISCAT_Vi_accepted_article.pdf https://eprints.lancs.ac.uk/id/eprint/86240/4/Yamazaki_et_al_2017_Journal_of_Geophysical_Research_Space_Physics.pdf https://doi.org/10.1002/2017JA023974 en eng https://eprints.lancs.ac.uk/id/eprint/86240/1/EISCAT_Vi_accepted_article.pdf https://eprints.lancs.ac.uk/id/eprint/86240/4/Yamazaki_et_al_2017_Journal_of_Geophysical_Research_Space_Physics.pdf Yamazaki, Yosuke and Kosch, Michael Jurgen and Ogawa, Yasunobu (2019) Average field-aligned ion velocity over the EISCAT radars. Journal of Geophysical Research: Space Physics, 122 (5). pp. 5630-5642. ISSN 2169-9402 creative_commons_attribution_noncommercial_4_0_international_license creative_commons_attribution_4_0_international_license Journal Article PeerReviewed 2019 ftulancaster https://doi.org/10.1002/2017JA023974 2023-08-03T22:31:28Z Long-term measurements by the European Incoherent Scatter (EISCAT) radars at Tromsø (69.6° N, 19.2° E) and Svalbard (78.2° N, 16.0° E) are used to determine the climatology of the field-aligned ion velocity in the F-region ionosphere (175–475 km) at high latitudes. The average ion velocity is calculated at various altitudes and times of day. The magnitude of the average field-aligned ion velocity is on the order of 10 m/s, similar to previous results at middle and low latitudes. The results obtained for the two radars are in good agreement. During daytime the direction of the average field-aligned ion velocity changes from downward to upward around 350 km, while during nighttime it is upward at all heights. The reversal height of the daytime field-aligned ion velocity depends on solar activity. It is elevated by more than 100 km during high solar flux periods compared to low solar flux periods. The Thermosphere Ionosphere Electrodynamics General Circulation Model (TIE-GCM) reproduces the main features of the field-aligned ion velocity climatology. The simulation results suggest that the plasma pressure gradient force and gravity force play a dominant role for the daytime field-aligned ion motion. The height pattern of the field-aligned ion velocity tends to be preserved in different solar activity conditions at constant pressure surfaces, but not at constant altitudes, which explains the observed dependence on solar activity. During nighttime, the effect of the neutral wind dominates the field-aligned ion velocity. Article in Journal/Newspaper EISCAT Svalbard Tromsø Lancaster University: Lancaster Eprints Svalbard Tromsø Journal of Geophysical Research: Space Physics 122 5 5630 5642 |
institution |
Open Polar |
collection |
Lancaster University: Lancaster Eprints |
op_collection_id |
ftulancaster |
language |
English |
description |
Long-term measurements by the European Incoherent Scatter (EISCAT) radars at Tromsø (69.6° N, 19.2° E) and Svalbard (78.2° N, 16.0° E) are used to determine the climatology of the field-aligned ion velocity in the F-region ionosphere (175–475 km) at high latitudes. The average ion velocity is calculated at various altitudes and times of day. The magnitude of the average field-aligned ion velocity is on the order of 10 m/s, similar to previous results at middle and low latitudes. The results obtained for the two radars are in good agreement. During daytime the direction of the average field-aligned ion velocity changes from downward to upward around 350 km, while during nighttime it is upward at all heights. The reversal height of the daytime field-aligned ion velocity depends on solar activity. It is elevated by more than 100 km during high solar flux periods compared to low solar flux periods. The Thermosphere Ionosphere Electrodynamics General Circulation Model (TIE-GCM) reproduces the main features of the field-aligned ion velocity climatology. The simulation results suggest that the plasma pressure gradient force and gravity force play a dominant role for the daytime field-aligned ion motion. The height pattern of the field-aligned ion velocity tends to be preserved in different solar activity conditions at constant pressure surfaces, but not at constant altitudes, which explains the observed dependence on solar activity. During nighttime, the effect of the neutral wind dominates the field-aligned ion velocity. |
format |
Article in Journal/Newspaper |
author |
Yamazaki, Yosuke Kosch, Michael Jurgen Ogawa, Yasunobu |
spellingShingle |
Yamazaki, Yosuke Kosch, Michael Jurgen Ogawa, Yasunobu Average field-aligned ion velocity over the EISCAT radars |
author_facet |
Yamazaki, Yosuke Kosch, Michael Jurgen Ogawa, Yasunobu |
author_sort |
Yamazaki, Yosuke |
title |
Average field-aligned ion velocity over the EISCAT radars |
title_short |
Average field-aligned ion velocity over the EISCAT radars |
title_full |
Average field-aligned ion velocity over the EISCAT radars |
title_fullStr |
Average field-aligned ion velocity over the EISCAT radars |
title_full_unstemmed |
Average field-aligned ion velocity over the EISCAT radars |
title_sort |
average field-aligned ion velocity over the eiscat radars |
publishDate |
2019 |
url |
https://eprints.lancs.ac.uk/id/eprint/86240/ https://eprints.lancs.ac.uk/id/eprint/86240/1/EISCAT_Vi_accepted_article.pdf https://eprints.lancs.ac.uk/id/eprint/86240/4/Yamazaki_et_al_2017_Journal_of_Geophysical_Research_Space_Physics.pdf https://doi.org/10.1002/2017JA023974 |
geographic |
Svalbard Tromsø |
geographic_facet |
Svalbard Tromsø |
genre |
EISCAT Svalbard Tromsø |
genre_facet |
EISCAT Svalbard Tromsø |
op_relation |
https://eprints.lancs.ac.uk/id/eprint/86240/1/EISCAT_Vi_accepted_article.pdf https://eprints.lancs.ac.uk/id/eprint/86240/4/Yamazaki_et_al_2017_Journal_of_Geophysical_Research_Space_Physics.pdf Yamazaki, Yosuke and Kosch, Michael Jurgen and Ogawa, Yasunobu (2019) Average field-aligned ion velocity over the EISCAT radars. Journal of Geophysical Research: Space Physics, 122 (5). pp. 5630-5642. ISSN 2169-9402 |
op_rights |
creative_commons_attribution_noncommercial_4_0_international_license creative_commons_attribution_4_0_international_license |
op_doi |
https://doi.org/10.1002/2017JA023974 |
container_title |
Journal of Geophysical Research: Space Physics |
container_volume |
122 |
container_issue |
5 |
container_start_page |
5630 |
op_container_end_page |
5642 |
_version_ |
1775350383185494016 |