Even moderate geomagnetic pulsations can cause fluctuations of fo F2 frequency of the auroral ionosphere
The ionosonde at the Sodankylä Geophysical Observatory (SOD; 67 ∘ N, 27 ∘ E; Finland) routinely performs vertical sounding once per minute which enables the study of fast ionospheric variations at a frequency of the long-period geomagnetic pulsations Pc5–6/Pi3 (1–5 mHz). Using the ionosonde data fro...
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ftdoajarticles:oai:doaj.org/article:d5d924de8c5445ff8bc0bce275aa5cc9 2023-05-15T18:20:18+02:00 Even moderate geomagnetic pulsations can cause fluctuations of fo F2 frequency of the auroral ionosphere N. Yagova A. Kozlovsky E. Fedorov O. Kozyreva 2021-06-01T00:00:00Z https://doi.org/10.5194/angeo-39-549-2021 https://doaj.org/article/d5d924de8c5445ff8bc0bce275aa5cc9 EN eng Copernicus Publications https://angeo.copernicus.org/articles/39/549/2021/angeo-39-549-2021.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-39-549-2021 0992-7689 1432-0576 https://doaj.org/article/d5d924de8c5445ff8bc0bce275aa5cc9 Annales Geophysicae, Vol 39, Pp 549-562 (2021) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2021 ftdoajarticles https://doi.org/10.5194/angeo-39-549-2021 2022-12-31T07:59:39Z The ionosonde at the Sodankylä Geophysical Observatory (SOD; 67 ∘ N, 27 ∘ E; Finland) routinely performs vertical sounding once per minute which enables the study of fast ionospheric variations at a frequency of the long-period geomagnetic pulsations Pc5–6/Pi3 (1–5 mHz). Using the ionosonde data from April 2014–December 2015 and colocated geomagnetic measurements, we have investigated a correspondence between the magnetic field pulsations and variations of the critical frequency of radio waves reflected from the ionospheric F2 layer ( fo F2). For this study, we have developed a technique for automated retrieval of the critical frequency of the F2 layer from ionograms. As a rule, the Pc5–6/Pi3 frequency band fluctuations in fo F2 were observed at daytime during quiet or moderately disturbed space weather conditions. In most cases (about 80 % ), the coherence between the fo F2 variations and geomagnetic pulsations was low. However in some cases (specified as “coherent”) the coherence was as large as γ 2 ≥0.5 . The following conditions are favorable for the occurrence of coherent cases: enhanced auroral activity (6 h maximal auroral electrojet (AE) ≥800 nT), high solar wind speed ( V >600 km/s), fluctuating solar wind pressure and northward interplanetary magnetic field. In the cases when the coherence was higher at shorter periods of oscillations, the magnetic pulsations demonstrated features typical for the Alfvén field line resonance. Article in Journal/Newspaper Sodankylä Directory of Open Access Journals: DOAJ Articles Sodankylä ENVELOPE(26.600,26.600,67.417,67.417) Annales Geophysicae 39 3 549 562 |
institution |
Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 N. Yagova A. Kozlovsky E. Fedorov O. Kozyreva Even moderate geomagnetic pulsations can cause fluctuations of fo F2 frequency of the auroral ionosphere |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
The ionosonde at the Sodankylä Geophysical Observatory (SOD; 67 ∘ N, 27 ∘ E; Finland) routinely performs vertical sounding once per minute which enables the study of fast ionospheric variations at a frequency of the long-period geomagnetic pulsations Pc5–6/Pi3 (1–5 mHz). Using the ionosonde data from April 2014–December 2015 and colocated geomagnetic measurements, we have investigated a correspondence between the magnetic field pulsations and variations of the critical frequency of radio waves reflected from the ionospheric F2 layer ( fo F2). For this study, we have developed a technique for automated retrieval of the critical frequency of the F2 layer from ionograms. As a rule, the Pc5–6/Pi3 frequency band fluctuations in fo F2 were observed at daytime during quiet or moderately disturbed space weather conditions. In most cases (about 80 % ), the coherence between the fo F2 variations and geomagnetic pulsations was low. However in some cases (specified as “coherent”) the coherence was as large as γ 2 ≥0.5 . The following conditions are favorable for the occurrence of coherent cases: enhanced auroral activity (6 h maximal auroral electrojet (AE) ≥800 nT), high solar wind speed ( V >600 km/s), fluctuating solar wind pressure and northward interplanetary magnetic field. In the cases when the coherence was higher at shorter periods of oscillations, the magnetic pulsations demonstrated features typical for the Alfvén field line resonance. |
format |
Article in Journal/Newspaper |
author |
N. Yagova A. Kozlovsky E. Fedorov O. Kozyreva |
author_facet |
N. Yagova A. Kozlovsky E. Fedorov O. Kozyreva |
author_sort |
N. Yagova |
title |
Even moderate geomagnetic pulsations can cause fluctuations of fo F2 frequency of the auroral ionosphere |
title_short |
Even moderate geomagnetic pulsations can cause fluctuations of fo F2 frequency of the auroral ionosphere |
title_full |
Even moderate geomagnetic pulsations can cause fluctuations of fo F2 frequency of the auroral ionosphere |
title_fullStr |
Even moderate geomagnetic pulsations can cause fluctuations of fo F2 frequency of the auroral ionosphere |
title_full_unstemmed |
Even moderate geomagnetic pulsations can cause fluctuations of fo F2 frequency of the auroral ionosphere |
title_sort |
even moderate geomagnetic pulsations can cause fluctuations of fo f2 frequency of the auroral ionosphere |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/angeo-39-549-2021 https://doaj.org/article/d5d924de8c5445ff8bc0bce275aa5cc9 |
long_lat |
ENVELOPE(26.600,26.600,67.417,67.417) |
geographic |
Sodankylä |
geographic_facet |
Sodankylä |
genre |
Sodankylä |
genre_facet |
Sodankylä |
op_source |
Annales Geophysicae, Vol 39, Pp 549-562 (2021) |
op_relation |
https://angeo.copernicus.org/articles/39/549/2021/angeo-39-549-2021.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-39-549-2021 0992-7689 1432-0576 https://doaj.org/article/d5d924de8c5445ff8bc0bce275aa5cc9 |
op_doi |
https://doi.org/10.5194/angeo-39-549-2021 |
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Annales Geophysicae |
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39 |
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3 |
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549 |
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562 |
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