Artificial periodic irregularities in the auroral ionosphere
Artificial periodic irregularities (API) are produced in the ionospheric plasma by a powerful standing electromagnetic wave reflected off the F region. The resulting electron-density irregularities can scatter other high-frequency waves if the Bragg scattering condition is met. Such measurements hav...
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ftdoajarticles:oai:doaj.org/article:45bab62242e04d20aefdcb8dab2ed80d 2023-05-15T16:04:50+02:00 Artificial periodic irregularities in the auroral ionosphere M. T. Rietveld E. Turunen H. Matveinen N. P. Goncharov P. Pollari 1996-12-01T00:00:00Z https://doi.org/10.1007/s00585-996-1437-0 https://doaj.org/article/45bab62242e04d20aefdcb8dab2ed80d EN eng Copernicus Publications https://www.ann-geophys.net/14/1437/1996/angeo-14-1437-1996.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.1007/s00585-996-1437-0 0992-7689 1432-0576 https://doaj.org/article/45bab62242e04d20aefdcb8dab2ed80d Annales Geophysicae, Vol 14, Pp 1437-1453 (1996) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 1996 ftdoajarticles https://doi.org/10.1007/s00585-996-1437-0 2022-12-31T15:24:24Z Artificial periodic irregularities (API) are produced in the ionospheric plasma by a powerful standing electromagnetic wave reflected off the F region. The resulting electron-density irregularities can scatter other high-frequency waves if the Bragg scattering condition is met. Such measurements have been performed at mid-latitudes for two decades and have been developed into a useful ionospheric diagnostic technique. We report here the first measurements from a high-latitude station, using the EISCAT heating facility near Tromsø, Norway. Both F-region and lower-altitude ionospheric echoes have been obtained, but the bulk of the data has been in the E and D regions with echoes extending down to 52-km altitude. Examples of API are shown, mainly from the D region, together with simultaneous VHF incoherent-scatter-radar (ISR) data. Vertical velocities derived from the rate of phase change during the irregularity decay are shown and compared with velocities derived from the ISR. Some of the API-derived velocities in the 75–115-km height range appear consistent with vertical neutral winds as shown by their magnitudes and by evidence of gravity waves, while other data in the 50–70-km range show an unrealistically large bias. For a comparison with ISR data it has proved difficult to get good quality data sets overlapping in height and time. The initial comparisons show some agreement, but discrepancies of several metres per second do not yet allow us to conclude that the two techniques are measuring the same quantity. The irregularity decay time-constants between about 53 and 70 km are compared with the results of an advanced ion-chemistry model, and height profiles of recorded signal power are compared with model estimates in the same altitude range. The calculated amplitude shows good agreement with the data in that the maximum occurs at about the same height as that of the measured amplitude. The calculated time-constant agrees very well with the data below 60 km but is larger above 60 km by a factor of up to 2 at ... Article in Journal/Newspaper EISCAT Tromsø Directory of Open Access Journals: DOAJ Articles Norway Tromsø Annales Geophysicae 14 12 1437 1453 |
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Directory of Open Access Journals: DOAJ Articles |
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Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
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Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 M. T. Rietveld E. Turunen H. Matveinen N. P. Goncharov P. Pollari Artificial periodic irregularities in the auroral ionosphere |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
Artificial periodic irregularities (API) are produced in the ionospheric plasma by a powerful standing electromagnetic wave reflected off the F region. The resulting electron-density irregularities can scatter other high-frequency waves if the Bragg scattering condition is met. Such measurements have been performed at mid-latitudes for two decades and have been developed into a useful ionospheric diagnostic technique. We report here the first measurements from a high-latitude station, using the EISCAT heating facility near Tromsø, Norway. Both F-region and lower-altitude ionospheric echoes have been obtained, but the bulk of the data has been in the E and D regions with echoes extending down to 52-km altitude. Examples of API are shown, mainly from the D region, together with simultaneous VHF incoherent-scatter-radar (ISR) data. Vertical velocities derived from the rate of phase change during the irregularity decay are shown and compared with velocities derived from the ISR. Some of the API-derived velocities in the 75–115-km height range appear consistent with vertical neutral winds as shown by their magnitudes and by evidence of gravity waves, while other data in the 50–70-km range show an unrealistically large bias. For a comparison with ISR data it has proved difficult to get good quality data sets overlapping in height and time. The initial comparisons show some agreement, but discrepancies of several metres per second do not yet allow us to conclude that the two techniques are measuring the same quantity. The irregularity decay time-constants between about 53 and 70 km are compared with the results of an advanced ion-chemistry model, and height profiles of recorded signal power are compared with model estimates in the same altitude range. The calculated amplitude shows good agreement with the data in that the maximum occurs at about the same height as that of the measured amplitude. The calculated time-constant agrees very well with the data below 60 km but is larger above 60 km by a factor of up to 2 at ... |
format |
Article in Journal/Newspaper |
author |
M. T. Rietveld E. Turunen H. Matveinen N. P. Goncharov P. Pollari |
author_facet |
M. T. Rietveld E. Turunen H. Matveinen N. P. Goncharov P. Pollari |
author_sort |
M. T. Rietveld |
title |
Artificial periodic irregularities in the auroral ionosphere |
title_short |
Artificial periodic irregularities in the auroral ionosphere |
title_full |
Artificial periodic irregularities in the auroral ionosphere |
title_fullStr |
Artificial periodic irregularities in the auroral ionosphere |
title_full_unstemmed |
Artificial periodic irregularities in the auroral ionosphere |
title_sort |
artificial periodic irregularities in the auroral ionosphere |
publisher |
Copernicus Publications |
publishDate |
1996 |
url |
https://doi.org/10.1007/s00585-996-1437-0 https://doaj.org/article/45bab62242e04d20aefdcb8dab2ed80d |
geographic |
Norway Tromsø |
geographic_facet |
Norway Tromsø |
genre |
EISCAT Tromsø |
genre_facet |
EISCAT Tromsø |
op_source |
Annales Geophysicae, Vol 14, Pp 1437-1453 (1996) |
op_relation |
https://www.ann-geophys.net/14/1437/1996/angeo-14-1437-1996.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.1007/s00585-996-1437-0 0992-7689 1432-0576 https://doaj.org/article/45bab62242e04d20aefdcb8dab2ed80d |
op_doi |
https://doi.org/10.1007/s00585-996-1437-0 |
container_title |
Annales Geophysicae |
container_volume |
14 |
container_issue |
12 |
container_start_page |
1437 |
op_container_end_page |
1453 |
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1766400477295017984 |