Sunset transition of negative charge in the D-region ionosphere during high-ionization conditions
The solar proton event of October 1989 and especially the sunset of 23October is examined in this study of negative ion chemistry, which combines measurements of nitric oxide, electron density, and cosmic radio noise absorption with ion and neutral chemistry modelling. Model results show that the ne...
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ftcopernicus:oai:publications.copernicus.org:angeo35720 2023-05-15T16:04:43+02:00 Sunset transition of negative charge in the D-region ionosphere during high-ionization conditions Verronen, P. T. Ulich, Th. Turunen, E. Rodger, C. J. 2018-09-27 application/pdf https://doi.org/10.5194/angeo-24-187-2006 https://angeo.copernicus.org/articles/24/187/2006/ eng eng doi:10.5194/angeo-24-187-2006 https://angeo.copernicus.org/articles/24/187/2006/ eISSN: 1432-0576 Text 2018 ftcopernicus https://doi.org/10.5194/angeo-24-187-2006 2020-07-20T16:27:18Z The solar proton event of October 1989 and especially the sunset of 23October is examined in this study of negative ion chemistry, which combines measurements of nitric oxide, electron density, and cosmic radio noise absorption with ion and neutral chemistry modelling. Model results show that the negative charge transition from electrons to negative ions during sunset occurs at altitudes below 80 km and is dependent on both ultraviolet and visible solar radiation. The ultraviolet effect is mostly due to rapid changes in atomic oxygen and O 2 ( 1 Δ g ), while the decrease in NO 3 - photodetachment plays a minor role. The effect driven by visible wavelengths is due to changes in photodissociation of CO 3 - and the subsequent electron photodetachment from O - , and at higher altitudes is also due to a decrease in the photodetachment of O 2 - . The relative sizes of the ultraviolet and visible effects vary with altitude, with the visible effects increasing in importance at higher altitudes, and they are also controlled by the nitric oxide concentration. These modelling results are in good agreement with EISCAT incoherent scatter radar and Kilpisjärvi riometer measurements. Text EISCAT Kilpisjärvi Copernicus Publications: E-Journals Kilpisjärvi ENVELOPE(20.767,20.767,69.034,69.034) Annales Geophysicae 24 1 187 202 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The solar proton event of October 1989 and especially the sunset of 23October is examined in this study of negative ion chemistry, which combines measurements of nitric oxide, electron density, and cosmic radio noise absorption with ion and neutral chemistry modelling. Model results show that the negative charge transition from electrons to negative ions during sunset occurs at altitudes below 80 km and is dependent on both ultraviolet and visible solar radiation. The ultraviolet effect is mostly due to rapid changes in atomic oxygen and O 2 ( 1 Δ g ), while the decrease in NO 3 - photodetachment plays a minor role. The effect driven by visible wavelengths is due to changes in photodissociation of CO 3 - and the subsequent electron photodetachment from O - , and at higher altitudes is also due to a decrease in the photodetachment of O 2 - . The relative sizes of the ultraviolet and visible effects vary with altitude, with the visible effects increasing in importance at higher altitudes, and they are also controlled by the nitric oxide concentration. These modelling results are in good agreement with EISCAT incoherent scatter radar and Kilpisjärvi riometer measurements. |
format |
Text |
author |
Verronen, P. T. Ulich, Th. Turunen, E. Rodger, C. J. |
spellingShingle |
Verronen, P. T. Ulich, Th. Turunen, E. Rodger, C. J. Sunset transition of negative charge in the D-region ionosphere during high-ionization conditions |
author_facet |
Verronen, P. T. Ulich, Th. Turunen, E. Rodger, C. J. |
author_sort |
Verronen, P. T. |
title |
Sunset transition of negative charge in the D-region ionosphere during high-ionization conditions |
title_short |
Sunset transition of negative charge in the D-region ionosphere during high-ionization conditions |
title_full |
Sunset transition of negative charge in the D-region ionosphere during high-ionization conditions |
title_fullStr |
Sunset transition of negative charge in the D-region ionosphere during high-ionization conditions |
title_full_unstemmed |
Sunset transition of negative charge in the D-region ionosphere during high-ionization conditions |
title_sort |
sunset transition of negative charge in the d-region ionosphere during high-ionization conditions |
publishDate |
2018 |
url |
https://doi.org/10.5194/angeo-24-187-2006 https://angeo.copernicus.org/articles/24/187/2006/ |
long_lat |
ENVELOPE(20.767,20.767,69.034,69.034) |
geographic |
Kilpisjärvi |
geographic_facet |
Kilpisjärvi |
genre |
EISCAT Kilpisjärvi |
genre_facet |
EISCAT Kilpisjärvi |
op_source |
eISSN: 1432-0576 |
op_relation |
doi:10.5194/angeo-24-187-2006 https://angeo.copernicus.org/articles/24/187/2006/ |
op_doi |
https://doi.org/10.5194/angeo-24-187-2006 |
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Annales Geophysicae |
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24 |
container_issue |
1 |
container_start_page |
187 |
op_container_end_page |
202 |
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1766400343532371968 |