STARE velocity at large flow angles: is it related to the ion acoustic speed?
The electron drift and ion-acoustic speed in the E region inferred from EISCAT measurements are compared with concurrent STARE radar velocity data to investigate a recent hypothesis by Bahcivan et al.(2005), that the electrojet irregularity velocity at large flow angles is simply the product of the...
Published in: | Annales Geophysicae |
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Online Access: | https://doi.org/10.5194/angeo-24-873-2006 https://angeo.copernicus.org/articles/24/873/2006/ |
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ftcopernicus:oai:publications.copernicus.org:angeo35809 2023-05-15T16:04:32+02:00 STARE velocity at large flow angles: is it related to the ion acoustic speed? Uspensky, M. V. Koustov, A. V. Nozawa, S. 2018-09-27 application/pdf https://doi.org/10.5194/angeo-24-873-2006 https://angeo.copernicus.org/articles/24/873/2006/ eng eng doi:10.5194/angeo-24-873-2006 https://angeo.copernicus.org/articles/24/873/2006/ eISSN: 1432-0576 Text 2018 ftcopernicus https://doi.org/10.5194/angeo-24-873-2006 2020-07-20T16:27:17Z The electron drift and ion-acoustic speed in the E region inferred from EISCAT measurements are compared with concurrent STARE radar velocity data to investigate a recent hypothesis by Bahcivan et al.(2005), that the electrojet irregularity velocity at large flow angles is simply the product of the ion-acoustic speed and the cosine of an angle between the electron flow and the irregularity propagation direction. About 3000 measurements for flow angles of 50°–70° and electron drifts of 400–1500 m/s are considered. It is shown that the correlation coefficient and the slope of the best linear fit line between the predicted STARE velocity (based solely on EISCAT data and the hypothesis of Bahcivan et al.(2005)) and the measured one are both of the order of ~0.4. Velocity predictions are somewhat better if one assumes that the irregularity phase velocity is the line-of-sight component of the E × B drift scaled down by a factor ~0.6 due to off-orthogonality of irregularity propagation (nonzero effective aspect angles of STARE observations). Text EISCAT Copernicus Publications: E-Journals Annales Geophysicae 24 3 873 885 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The electron drift and ion-acoustic speed in the E region inferred from EISCAT measurements are compared with concurrent STARE radar velocity data to investigate a recent hypothesis by Bahcivan et al.(2005), that the electrojet irregularity velocity at large flow angles is simply the product of the ion-acoustic speed and the cosine of an angle between the electron flow and the irregularity propagation direction. About 3000 measurements for flow angles of 50°–70° and electron drifts of 400–1500 m/s are considered. It is shown that the correlation coefficient and the slope of the best linear fit line between the predicted STARE velocity (based solely on EISCAT data and the hypothesis of Bahcivan et al.(2005)) and the measured one are both of the order of ~0.4. Velocity predictions are somewhat better if one assumes that the irregularity phase velocity is the line-of-sight component of the E × B drift scaled down by a factor ~0.6 due to off-orthogonality of irregularity propagation (nonzero effective aspect angles of STARE observations). |
format |
Text |
author |
Uspensky, M. V. Koustov, A. V. Nozawa, S. |
spellingShingle |
Uspensky, M. V. Koustov, A. V. Nozawa, S. STARE velocity at large flow angles: is it related to the ion acoustic speed? |
author_facet |
Uspensky, M. V. Koustov, A. V. Nozawa, S. |
author_sort |
Uspensky, M. V. |
title |
STARE velocity at large flow angles: is it related to the ion acoustic speed? |
title_short |
STARE velocity at large flow angles: is it related to the ion acoustic speed? |
title_full |
STARE velocity at large flow angles: is it related to the ion acoustic speed? |
title_fullStr |
STARE velocity at large flow angles: is it related to the ion acoustic speed? |
title_full_unstemmed |
STARE velocity at large flow angles: is it related to the ion acoustic speed? |
title_sort |
stare velocity at large flow angles: is it related to the ion acoustic speed? |
publishDate |
2018 |
url |
https://doi.org/10.5194/angeo-24-873-2006 https://angeo.copernicus.org/articles/24/873/2006/ |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
eISSN: 1432-0576 |
op_relation |
doi:10.5194/angeo-24-873-2006 https://angeo.copernicus.org/articles/24/873/2006/ |
op_doi |
https://doi.org/10.5194/angeo-24-873-2006 |
container_title |
Annales Geophysicae |
container_volume |
24 |
container_issue |
3 |
container_start_page |
873 |
op_container_end_page |
885 |
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1766400115870793728 |