Simultaneous observations at different altitudes of ionospheric backscatter in the eastward electrojet
International audience A common feature of evening near-range ionospheric backscatter in the CUTLASS Iceland radar field of view is two parallel, approximately L -shell-aligned regions of westward flow which are attributed to irregularities in the auroral eastward electrojet region of the ionosphere...
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ftinsu:oai:HAL:hal-00316344v1 2023-11-12T04:19:13+01:00 Simultaneous observations at different altitudes of ionospheric backscatter in the eastward electrojet Milan, S. E. Lester, M. Department of Physics and Astronomy Leicester University of Leicester 1998 https://hal.science/hal-00316344 https://hal.science/hal-00316344/document https://hal.science/hal-00316344/file/angeo-16-55-1998.pdf en eng HAL CCSD European Geosciences Union hal-00316344 https://hal.science/hal-00316344 https://hal.science/hal-00316344/document https://hal.science/hal-00316344/file/angeo-16-55-1998.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316344 Annales Geophysicae, 1998, 16 (1), pp.55-68 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 1998 ftinsu 2023-10-25T16:25:39Z International audience A common feature of evening near-range ionospheric backscatter in the CUTLASS Iceland radar field of view is two parallel, approximately L -shell-aligned regions of westward flow which are attributed to irregularities in the auroral eastward electrojet region of the ionosphere. These backscatter channels are separated by approximately 100?200 km in range. The orientation of the CUTLASS Iceland radar beams and the zonally aligned nature of the flow allows an approximate determination of flow angle to be made without the necessity of bistatic measurements. The two flow channels have different azimuthal variations in flow velocity and spectral width. The nearer of the two regions has two distinct spectral signatures. The eastern beams detect spectra with velocities which saturate at or near the ion-acoustic speed, and have low spectral widths (less than 100 m s ?1 ), while the western beams detect lower velocities and higher spectral widths (above 200 m s ?1 ). The more distant of the two channels has only one spectral signature with velocities above the ion-acoustic speed and high spectral widths. The spectral characteristics of the backscatter are consistent with E-region scatter in the nearer channel and upper-E-region or F-region scatter in the further channel. Temporal variations in the characteristics of both channels support current theories of E-region turbulent heating and previous observations of velocity-dependent backscatter cross-section. In future, observations of this nature will provide a powerful tool for the investigation of simultaneous E- and F-region irregularity generation under similar (nearly co-located or magnetically conjugate) electric field conditions. Article in Journal/Newspaper Iceland Institut national des sciences de l'Univers: HAL-INSU |
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Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Milan, S. E. Lester, M. Simultaneous observations at different altitudes of ionospheric backscatter in the eastward electrojet |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience A common feature of evening near-range ionospheric backscatter in the CUTLASS Iceland radar field of view is two parallel, approximately L -shell-aligned regions of westward flow which are attributed to irregularities in the auroral eastward electrojet region of the ionosphere. These backscatter channels are separated by approximately 100?200 km in range. The orientation of the CUTLASS Iceland radar beams and the zonally aligned nature of the flow allows an approximate determination of flow angle to be made without the necessity of bistatic measurements. The two flow channels have different azimuthal variations in flow velocity and spectral width. The nearer of the two regions has two distinct spectral signatures. The eastern beams detect spectra with velocities which saturate at or near the ion-acoustic speed, and have low spectral widths (less than 100 m s ?1 ), while the western beams detect lower velocities and higher spectral widths (above 200 m s ?1 ). The more distant of the two channels has only one spectral signature with velocities above the ion-acoustic speed and high spectral widths. The spectral characteristics of the backscatter are consistent with E-region scatter in the nearer channel and upper-E-region or F-region scatter in the further channel. Temporal variations in the characteristics of both channels support current theories of E-region turbulent heating and previous observations of velocity-dependent backscatter cross-section. In future, observations of this nature will provide a powerful tool for the investigation of simultaneous E- and F-region irregularity generation under similar (nearly co-located or magnetically conjugate) electric field conditions. |
author2 |
Department of Physics and Astronomy Leicester University of Leicester |
format |
Article in Journal/Newspaper |
author |
Milan, S. E. Lester, M. |
author_facet |
Milan, S. E. Lester, M. |
author_sort |
Milan, S. E. |
title |
Simultaneous observations at different altitudes of ionospheric backscatter in the eastward electrojet |
title_short |
Simultaneous observations at different altitudes of ionospheric backscatter in the eastward electrojet |
title_full |
Simultaneous observations at different altitudes of ionospheric backscatter in the eastward electrojet |
title_fullStr |
Simultaneous observations at different altitudes of ionospheric backscatter in the eastward electrojet |
title_full_unstemmed |
Simultaneous observations at different altitudes of ionospheric backscatter in the eastward electrojet |
title_sort |
simultaneous observations at different altitudes of ionospheric backscatter in the eastward electrojet |
publisher |
HAL CCSD |
publishDate |
1998 |
url |
https://hal.science/hal-00316344 https://hal.science/hal-00316344/document https://hal.science/hal-00316344/file/angeo-16-55-1998.pdf |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316344 Annales Geophysicae, 1998, 16 (1), pp.55-68 |
op_relation |
hal-00316344 https://hal.science/hal-00316344 https://hal.science/hal-00316344/document https://hal.science/hal-00316344/file/angeo-16-55-1998.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782335710369415168 |