HF echo types revisited: aspect angle attenuation effects
The high-spatial-resolution observations of the auroral E-region echoes by the Super Dual Auroral Radar Network (SuperDARN) HF radar at Pykkvibaer, Iceland considered in a previous study are re-examined. Both the spectral power and Doppler velocity of the E-region HF echoes exhibit strong dependence...
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ftdoajarticles:oai:doaj.org/article:d141b0c222b54b26905961acca754ff5 2023-05-15T16:50:06+02:00 HF echo types revisited: aspect angle attenuation effects R. A. Makarevich B. A. Carter 2009-08-01T00:00:00Z https://doi.org/10.5194/angeo-27-3065-2009 https://doaj.org/article/d141b0c222b54b26905961acca754ff5 EN eng Copernicus Publications https://www.ann-geophys.net/27/3065/2009/angeo-27-3065-2009.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-27-3065-2009 0992-7689 1432-0576 https://doaj.org/article/d141b0c222b54b26905961acca754ff5 Annales Geophysicae, Vol 27, Pp 3065-3075 (2009) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2009 ftdoajarticles https://doi.org/10.5194/angeo-27-3065-2009 2022-12-31T10:09:36Z The high-spatial-resolution observations of the auroral E-region echoes by the Super Dual Auroral Radar Network (SuperDARN) HF radar at Pykkvibaer, Iceland considered in a previous study are re-examined. Both the spectral power and Doppler velocity of the E-region HF echoes exhibit strong dependence on the slant range and expected off-perpendicular magnetic aspect angle (aspect angle attenuation). We consider the aspect angle attenuation effects in identification of spectral HF echo types. It is argued that echoes with Doppler velocities close to the nominal value of the ion-acoustic speed C s (~350 m/s) and echoes with velocities greatly exceeding the C s (up to 600 m/s) are more related in their generation mechanisms than previously thought. It is proposed to treat the echoes near the C s as aspect-angle-attenuated counterparts of the high-velocity echoes and that both types are generated directly by the modified two-stream instability with aspect angle attenuation resulting in the preferential phase velocity saturation at the C s . Article in Journal/Newspaper Iceland Directory of Open Access Journals: DOAJ Articles Annales Geophysicae 27 8 3065 3075 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
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 R. A. Makarevich B. A. Carter HF echo types revisited: aspect angle attenuation effects |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
The high-spatial-resolution observations of the auroral E-region echoes by the Super Dual Auroral Radar Network (SuperDARN) HF radar at Pykkvibaer, Iceland considered in a previous study are re-examined. Both the spectral power and Doppler velocity of the E-region HF echoes exhibit strong dependence on the slant range and expected off-perpendicular magnetic aspect angle (aspect angle attenuation). We consider the aspect angle attenuation effects in identification of spectral HF echo types. It is argued that echoes with Doppler velocities close to the nominal value of the ion-acoustic speed C s (~350 m/s) and echoes with velocities greatly exceeding the C s (up to 600 m/s) are more related in their generation mechanisms than previously thought. It is proposed to treat the echoes near the C s as aspect-angle-attenuated counterparts of the high-velocity echoes and that both types are generated directly by the modified two-stream instability with aspect angle attenuation resulting in the preferential phase velocity saturation at the C s . |
format |
Article in Journal/Newspaper |
author |
R. A. Makarevich B. A. Carter |
author_facet |
R. A. Makarevich B. A. Carter |
author_sort |
R. A. Makarevich |
title |
HF echo types revisited: aspect angle attenuation effects |
title_short |
HF echo types revisited: aspect angle attenuation effects |
title_full |
HF echo types revisited: aspect angle attenuation effects |
title_fullStr |
HF echo types revisited: aspect angle attenuation effects |
title_full_unstemmed |
HF echo types revisited: aspect angle attenuation effects |
title_sort |
hf echo types revisited: aspect angle attenuation effects |
publisher |
Copernicus Publications |
publishDate |
2009 |
url |
https://doi.org/10.5194/angeo-27-3065-2009 https://doaj.org/article/d141b0c222b54b26905961acca754ff5 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Annales Geophysicae, Vol 27, Pp 3065-3075 (2009) |
op_relation |
https://www.ann-geophys.net/27/3065/2009/angeo-27-3065-2009.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-27-3065-2009 0992-7689 1432-0576 https://doaj.org/article/d141b0c222b54b26905961acca754ff5 |
op_doi |
https://doi.org/10.5194/angeo-27-3065-2009 |
container_title |
Annales Geophysicae |
container_volume |
27 |
container_issue |
8 |
container_start_page |
3065 |
op_container_end_page |
3075 |
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1766040292234887168 |