A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT
International audience An isolated region of energetic electron precipitation observed near local noon in the auroral zone has been investigated using imaging riometer (IRIS) and incoherent-scatter radar (EISCAT) techniques. IRIS revealed that the absorption event was essentially co-rotating with th...
Main Authors: | , , |
---|---|
Other Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
1996
|
Subjects: | |
Online Access: | https://hal.science/hal-00316252 https://hal.science/hal-00316252/document https://hal.science/hal-00316252/file/angeo-14-1305-1996.pdf |
id |
ftinsu:oai:HAL:hal-00316252v1 |
---|---|
record_format |
openpolar |
spelling |
ftinsu:oai:HAL:hal-00316252v1 2023-11-12T04:16:34+01:00 A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT Collis, P. N. Hargreaves, J. K. White, G. P. Engineering Department University of Cambridge UK (CAM) 1996 https://hal.science/hal-00316252 https://hal.science/hal-00316252/document https://hal.science/hal-00316252/file/angeo-14-1305-1996.pdf en eng HAL CCSD European Geosciences Union hal-00316252 https://hal.science/hal-00316252 https://hal.science/hal-00316252/document https://hal.science/hal-00316252/file/angeo-14-1305-1996.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316252 Annales Geophysicae, 1996, 14 (12), pp.1305-1316 [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 1996 ftinsu 2023-10-25T16:25:42Z International audience An isolated region of energetic electron precipitation observed near local noon in the auroral zone has been investigated using imaging riometer (IRIS) and incoherent-scatter radar (EISCAT) techniques. IRIS revealed that the absorption event was essentially co-rotating with the Earth for about 2 h. The spatial and temporal variations in D-region electron density seen by EISCAT were able to be interpreted within a proper context when compared with the IRIS data. EISCAT detected significant increases in electron density at altitudes as low as 65 km as the event drifted through the radar beam. The altitude distribution of incremental radio absorption revealed that more than half of the absorption occurred below 75 km, with a maximum of 67 km. The energy spectrum of the precipitating electrons was highly uniform throughout the event, and could be described analytically by the sum of three exponential distributions with characteristic energies of 6, 70 and 250 keV. A profile of effective recombination coefficient that resulted in self-consistent agreement between observed electron desities and those inferred from an inversion procedure has been deduced. The observations suggest a co-rotating magnetospheric source region on closed dayside field lines. However, a mechanism is required that can sustain such hard precipitation for the relatively long duration of the event. Article in Journal/Newspaper EISCAT Institut national des sciences de l'Univers: HAL-INSU |
institution |
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 Collis, P. N. Hargreaves, J. K. White, G. P. A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience An isolated region of energetic electron precipitation observed near local noon in the auroral zone has been investigated using imaging riometer (IRIS) and incoherent-scatter radar (EISCAT) techniques. IRIS revealed that the absorption event was essentially co-rotating with the Earth for about 2 h. The spatial and temporal variations in D-region electron density seen by EISCAT were able to be interpreted within a proper context when compared with the IRIS data. EISCAT detected significant increases in electron density at altitudes as low as 65 km as the event drifted through the radar beam. The altitude distribution of incremental radio absorption revealed that more than half of the absorption occurred below 75 km, with a maximum of 67 km. The energy spectrum of the precipitating electrons was highly uniform throughout the event, and could be described analytically by the sum of three exponential distributions with characteristic energies of 6, 70 and 250 keV. A profile of effective recombination coefficient that resulted in self-consistent agreement between observed electron desities and those inferred from an inversion procedure has been deduced. The observations suggest a co-rotating magnetospheric source region on closed dayside field lines. However, a mechanism is required that can sustain such hard precipitation for the relatively long duration of the event. |
author2 |
Engineering Department University of Cambridge UK (CAM) |
format |
Article in Journal/Newspaper |
author |
Collis, P. N. Hargreaves, J. K. White, G. P. |
author_facet |
Collis, P. N. Hargreaves, J. K. White, G. P. |
author_sort |
Collis, P. N. |
title |
A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT |
title_short |
A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT |
title_full |
A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT |
title_fullStr |
A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT |
title_full_unstemmed |
A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT |
title_sort |
localised co-rotating auroral absorption event observed near noon using imaging riometer and eiscat |
publisher |
HAL CCSD |
publishDate |
1996 |
url |
https://hal.science/hal-00316252 https://hal.science/hal-00316252/document https://hal.science/hal-00316252/file/angeo-14-1305-1996.pdf |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316252 Annales Geophysicae, 1996, 14 (12), pp.1305-1316 |
op_relation |
hal-00316252 https://hal.science/hal-00316252 https://hal.science/hal-00316252/document https://hal.science/hal-00316252/file/angeo-14-1305-1996.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782333624578736128 |