Velocities of auroral coherent echoes at 12 and 144 MHz
Two Doppler coherent radar systems are currently working at Hankasalmi, Finland, the STARE and CUTLASS radars operating at ~144 MHz and ~12 MHz, respectively. The STARE beam 3 is nearly co-located with the CUTLASS beam 5, providing an opportunity for echo velocity comparison along the same direction...
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ftdoajarticles:oai:doaj.org/article:a32183e9076f4c2e98f082f0c54612e9 2023-05-15T16:04:46+02:00 Velocities of auroral coherent echoes at 12 and 144 MHz A. V. Koustov D. W. Danskin M. V. Uspensky T. Ogawa P. Janhunen N. Nishitani S. Nozawa M. Lester S. Milan 2002-10-01T00:00:00Z https://doi.org/10.5194/angeo-20-1647-2002 https://doaj.org/article/a32183e9076f4c2e98f082f0c54612e9 EN eng Copernicus Publications https://www.ann-geophys.net/20/1647/2002/angeo-20-1647-2002.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-20-1647-2002 0992-7689 1432-0576 https://doaj.org/article/a32183e9076f4c2e98f082f0c54612e9 Annales Geophysicae, Vol 20, Pp 1647-1661 (2002) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2002 ftdoajarticles https://doi.org/10.5194/angeo-20-1647-2002 2022-12-31T06:18:51Z Two Doppler coherent radar systems are currently working at Hankasalmi, Finland, the STARE and CUTLASS radars operating at ~144 MHz and ~12 MHz, respectively. The STARE beam 3 is nearly co-located with the CUTLASS beam 5, providing an opportunity for echo velocity comparison along the same direction but at significantly different radar frequencies. In this study we consider an event when STARE radar echoes are detected at the same ranges as CUT-LASS radar echoes. The observations are complemented by EISCAT measurements of the ionospheric electric field and electron density behaviour at one range of 900 km. Two separate situations are studied; for the first one, CUTLASS observed F-region echoes (including the range of the EIS-CAT measurements), while for the second one CUTLASS observed E-region echoes. In both cases STARE E-region measurements were available. We show that F-region CUT-LASS velocities agree well with the convection component along the CUTLASS radar beam, while STARE velocities are typically smaller by a factor of 2–3. For the second case, STARE velocities are found to be either smaller or larger than CUTLASS velocities, depending on the range. Plasma physics of E-and F-region irregularities is discussed in attempt to explain the inferred relationship between various velocities. Special attention is paid to ionospheric refraction that is important for the detection of 12-MHz echoes. Key words. Ionosphere (ionospheric irregularities; plasma waves and instabilities; auroral ionosphere) Article in Journal/Newspaper EISCAT Directory of Open Access Journals: DOAJ Articles Annales Geophysicae 20 10 1647 1661 |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
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English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 A. V. Koustov D. W. Danskin M. V. Uspensky T. Ogawa P. Janhunen N. Nishitani S. Nozawa M. Lester S. Milan Velocities of auroral coherent echoes at 12 and 144 MHz |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
Two Doppler coherent radar systems are currently working at Hankasalmi, Finland, the STARE and CUTLASS radars operating at ~144 MHz and ~12 MHz, respectively. The STARE beam 3 is nearly co-located with the CUTLASS beam 5, providing an opportunity for echo velocity comparison along the same direction but at significantly different radar frequencies. In this study we consider an event when STARE radar echoes are detected at the same ranges as CUT-LASS radar echoes. The observations are complemented by EISCAT measurements of the ionospheric electric field and electron density behaviour at one range of 900 km. Two separate situations are studied; for the first one, CUTLASS observed F-region echoes (including the range of the EIS-CAT measurements), while for the second one CUTLASS observed E-region echoes. In both cases STARE E-region measurements were available. We show that F-region CUT-LASS velocities agree well with the convection component along the CUTLASS radar beam, while STARE velocities are typically smaller by a factor of 2–3. For the second case, STARE velocities are found to be either smaller or larger than CUTLASS velocities, depending on the range. Plasma physics of E-and F-region irregularities is discussed in attempt to explain the inferred relationship between various velocities. Special attention is paid to ionospheric refraction that is important for the detection of 12-MHz echoes. Key words. Ionosphere (ionospheric irregularities; plasma waves and instabilities; auroral ionosphere) |
format |
Article in Journal/Newspaper |
author |
A. V. Koustov D. W. Danskin M. V. Uspensky T. Ogawa P. Janhunen N. Nishitani S. Nozawa M. Lester S. Milan |
author_facet |
A. V. Koustov D. W. Danskin M. V. Uspensky T. Ogawa P. Janhunen N. Nishitani S. Nozawa M. Lester S. Milan |
author_sort |
A. V. Koustov |
title |
Velocities of auroral coherent echoes at 12 and 144 MHz |
title_short |
Velocities of auroral coherent echoes at 12 and 144 MHz |
title_full |
Velocities of auroral coherent echoes at 12 and 144 MHz |
title_fullStr |
Velocities of auroral coherent echoes at 12 and 144 MHz |
title_full_unstemmed |
Velocities of auroral coherent echoes at 12 and 144 MHz |
title_sort |
velocities of auroral coherent echoes at 12 and 144 mhz |
publisher |
Copernicus Publications |
publishDate |
2002 |
url |
https://doi.org/10.5194/angeo-20-1647-2002 https://doaj.org/article/a32183e9076f4c2e98f082f0c54612e9 |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
Annales Geophysicae, Vol 20, Pp 1647-1661 (2002) |
op_relation |
https://www.ann-geophys.net/20/1647/2002/angeo-20-1647-2002.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-20-1647-2002 0992-7689 1432-0576 https://doaj.org/article/a32183e9076f4c2e98f082f0c54612e9 |
op_doi |
https://doi.org/10.5194/angeo-20-1647-2002 |
container_title |
Annales Geophysicae |
container_volume |
20 |
container_issue |
10 |
container_start_page |
1647 |
op_container_end_page |
1661 |
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1766400404883505152 |