On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere
The EISCAT (European Incoherent Scatter Scientific Association) Heating facility was used to transmit powerful high-frequency (HF) electromagnetic waves into the F-region ionosphere to enhance optical emissions at 557.7 and 630.0 nm from atomic oxygen. The emissions were imaged by several stations o...
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ftcopernicus:oai:publications.copernicus.org:angeo113108 2024-09-15T18:04:29+00:00 On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere Leyser, Thomas B. Sergienko, Tima Brändström, Urban Gustavsson, Björn Rietveld, Michael T. 2023-12-13 application/pdf https://doi.org/10.5194/angeo-41-589-2023 https://angeo.copernicus.org/articles/41/589/2023/ eng eng doi:10.5194/angeo-41-589-2023 https://angeo.copernicus.org/articles/41/589/2023/ eISSN: 1432-0576 Text 2023 ftcopernicus https://doi.org/10.5194/angeo-41-589-2023 2024-08-28T05:24:15Z The EISCAT (European Incoherent Scatter Scientific Association) Heating facility was used to transmit powerful high-frequency (HF) electromagnetic waves into the F-region ionosphere to enhance optical emissions at 557.7 and 630.0 nm from atomic oxygen. The emissions were imaged by several stations of ALIS (Auroral Large Imaging System) in northern Sweden, and the EISCAT UHF incoherent scatter radar was used to obtain plasma parameter values. The ratio of the 557.7 to 630.0 nm column emission rates changed from I 5577 / I 6300 ≈ 0.2 <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="79pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="e5a6f447dab47ab13e8243d70dee4cc3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="angeo-41-589-2023-ie00001.svg" width="79pt" height="14pt" src="angeo-41-589-2023-ie00001.png"/> </svg:svg> for the HF pump frequency f 0 =6.200 MHz ≈4.6 f e to I 5577 / I 6300 ≈ 0.5 <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="79pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="6565b9f54488f7c0f6a15aab7491c835"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="angeo-41-589-2023-ie00002.svg" width="79pt" height="14pt" src="angeo-41-589-2023-ie00002.png"/> </svg:svg> when f 0 =5.423 MHz ≲4 f e , where f e is the ionospheric electron gyro frequency. The observations are interpreted in terms of decreased electron heating efficiency and thereby weaker enhancement at 630.0 nm for f 0 =5.423 MHz ≲ 4 f e . The emissions at 557.7 nm are attributed to electron acceleration by upper hybrid waves of metre-scale wavelengths that can be excited with f 0 =5.423 MHz ≲ 4 f e . Text EISCAT Northern Sweden Copernicus Publications: E-Journals Annales Geophysicae 41 2 589 600 |
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Copernicus Publications: E-Journals |
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English |
description |
The EISCAT (European Incoherent Scatter Scientific Association) Heating facility was used to transmit powerful high-frequency (HF) electromagnetic waves into the F-region ionosphere to enhance optical emissions at 557.7 and 630.0 nm from atomic oxygen. The emissions were imaged by several stations of ALIS (Auroral Large Imaging System) in northern Sweden, and the EISCAT UHF incoherent scatter radar was used to obtain plasma parameter values. The ratio of the 557.7 to 630.0 nm column emission rates changed from I 5577 / I 6300 ≈ 0.2 <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="79pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="e5a6f447dab47ab13e8243d70dee4cc3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="angeo-41-589-2023-ie00001.svg" width="79pt" height="14pt" src="angeo-41-589-2023-ie00001.png"/> </svg:svg> for the HF pump frequency f 0 =6.200 MHz ≈4.6 f e to I 5577 / I 6300 ≈ 0.5 <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="79pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="6565b9f54488f7c0f6a15aab7491c835"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="angeo-41-589-2023-ie00002.svg" width="79pt" height="14pt" src="angeo-41-589-2023-ie00002.png"/> </svg:svg> when f 0 =5.423 MHz ≲4 f e , where f e is the ionospheric electron gyro frequency. The observations are interpreted in terms of decreased electron heating efficiency and thereby weaker enhancement at 630.0 nm for f 0 =5.423 MHz ≲ 4 f e . The emissions at 557.7 nm are attributed to electron acceleration by upper hybrid waves of metre-scale wavelengths that can be excited with f 0 =5.423 MHz ≲ 4 f e . |
format |
Text |
author |
Leyser, Thomas B. Sergienko, Tima Brändström, Urban Gustavsson, Björn Rietveld, Michael T. |
spellingShingle |
Leyser, Thomas B. Sergienko, Tima Brändström, Urban Gustavsson, Björn Rietveld, Michael T. On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere |
author_facet |
Leyser, Thomas B. Sergienko, Tima Brändström, Urban Gustavsson, Björn Rietveld, Michael T. |
author_sort |
Leyser, Thomas B. |
title |
On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere |
title_short |
On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere |
title_full |
On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere |
title_fullStr |
On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere |
title_full_unstemmed |
On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere |
title_sort |
on mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude f-region ionosphere |
publishDate |
2023 |
url |
https://doi.org/10.5194/angeo-41-589-2023 https://angeo.copernicus.org/articles/41/589/2023/ |
genre |
EISCAT Northern Sweden |
genre_facet |
EISCAT Northern Sweden |
op_source |
eISSN: 1432-0576 |
op_relation |
doi:10.5194/angeo-41-589-2023 https://angeo.copernicus.org/articles/41/589/2023/ |
op_doi |
https://doi.org/10.5194/angeo-41-589-2023 |
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Annales Geophysicae |
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41 |
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2 |
container_start_page |
589 |
op_container_end_page |
600 |
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1810441979197128704 |