Cosmic radio noise absorption events associated with equatorward drifting arcs during a substorm growth phase
International audience Cosmic radio noise absorption (CNA) events associated with equatorward drifting arcs during a substorm growth phase are studied by using simultaneous optical auroral, IRIS imaging riometer and EISCAT incoherent scatter radar measurements. The CNA is generally attributed to ene...
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ftccsdartic:oai:HAL:hal-00317349v1 2023-11-12T04:16:38+01:00 Cosmic radio noise absorption events associated with equatorward drifting arcs during a substorm growth phase Jussila, J. R. T. Aikio, A. T. Shalimov, S. Marple, S. R. Department of Physical Sciences Oulu University of Oulu Schmidt United Institute of Physics of the Earth Moscow (IPE) Russian Academy of Sciences Moscow (RAS) Department of Communication Systems 2004-04-08 https://hal.science/hal-00317349 https://hal.science/hal-00317349/document https://hal.science/hal-00317349/file/angeo-22-1675-2004.pdf en eng HAL CCSD European Geosciences Union hal-00317349 https://hal.science/hal-00317349 https://hal.science/hal-00317349/document https://hal.science/hal-00317349/file/angeo-22-1675-2004.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00317349 Annales Geophysicae, 2004, 22 (5), pp.1675-1686 [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 2004 ftccsdartic 2023-10-21T23:07:29Z International audience Cosmic radio noise absorption (CNA) events associated with equatorward drifting arcs during a substorm growth phase are studied by using simultaneous optical auroral, IRIS imaging riometer and EISCAT incoherent scatter radar measurements. The CNA is generally attributed to energetic particle precipitation in the D-region. However, it has been argued that plasma irregularities or enhanced electron temperature ( T e ) in the E-region could also produce CNA. Both of the latter mechanisms are related to intense electric fields in the ionosphere. We present two events which occur during a substorm growth phase in the evening MLT sector. In both of the events, an auroral arc is drifting equatorward, together with a region of CNA (auroral absorption bay) located on the equatorward side and outside of the arc. Both of the events are associated with enhanced D-region electron density on the equatorward side of the auroral arc, but in the second event, a region of intense electric field and enhanced electron temperature in the E-region is also located on the equatorward side of the arc. We show that in the studied events neither plasma instabilities nor enhanced T e play a significant role in producing the measured CNA, but the CNA in the vicinity of the equatorward drifting arcs is produced by D-region energetic electron precipitation. Key words. Ionosphere (auroral ionosphere; particle precipitation; electric fields and currents) Article in Journal/Newspaper EISCAT Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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Open Polar |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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ftccsdartic |
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 Jussila, J. R. T. Aikio, A. T. Shalimov, S. Marple, S. R. Cosmic radio noise absorption events associated with equatorward drifting arcs during a substorm growth phase |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience Cosmic radio noise absorption (CNA) events associated with equatorward drifting arcs during a substorm growth phase are studied by using simultaneous optical auroral, IRIS imaging riometer and EISCAT incoherent scatter radar measurements. The CNA is generally attributed to energetic particle precipitation in the D-region. However, it has been argued that plasma irregularities or enhanced electron temperature ( T e ) in the E-region could also produce CNA. Both of the latter mechanisms are related to intense electric fields in the ionosphere. We present two events which occur during a substorm growth phase in the evening MLT sector. In both of the events, an auroral arc is drifting equatorward, together with a region of CNA (auroral absorption bay) located on the equatorward side and outside of the arc. Both of the events are associated with enhanced D-region electron density on the equatorward side of the auroral arc, but in the second event, a region of intense electric field and enhanced electron temperature in the E-region is also located on the equatorward side of the arc. We show that in the studied events neither plasma instabilities nor enhanced T e play a significant role in producing the measured CNA, but the CNA in the vicinity of the equatorward drifting arcs is produced by D-region energetic electron precipitation. Key words. Ionosphere (auroral ionosphere; particle precipitation; electric fields and currents) |
author2 |
Department of Physical Sciences Oulu University of Oulu Schmidt United Institute of Physics of the Earth Moscow (IPE) Russian Academy of Sciences Moscow (RAS) Department of Communication Systems |
format |
Article in Journal/Newspaper |
author |
Jussila, J. R. T. Aikio, A. T. Shalimov, S. Marple, S. R. |
author_facet |
Jussila, J. R. T. Aikio, A. T. Shalimov, S. Marple, S. R. |
author_sort |
Jussila, J. R. T. |
title |
Cosmic radio noise absorption events associated with equatorward drifting arcs during a substorm growth phase |
title_short |
Cosmic radio noise absorption events associated with equatorward drifting arcs during a substorm growth phase |
title_full |
Cosmic radio noise absorption events associated with equatorward drifting arcs during a substorm growth phase |
title_fullStr |
Cosmic radio noise absorption events associated with equatorward drifting arcs during a substorm growth phase |
title_full_unstemmed |
Cosmic radio noise absorption events associated with equatorward drifting arcs during a substorm growth phase |
title_sort |
cosmic radio noise absorption events associated with equatorward drifting arcs during a substorm growth phase |
publisher |
HAL CCSD |
publishDate |
2004 |
url |
https://hal.science/hal-00317349 https://hal.science/hal-00317349/document https://hal.science/hal-00317349/file/angeo-22-1675-2004.pdf |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00317349 Annales Geophysicae, 2004, 22 (5), pp.1675-1686 |
op_relation |
hal-00317349 https://hal.science/hal-00317349 https://hal.science/hal-00317349/document https://hal.science/hal-00317349/file/angeo-22-1675-2004.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782333703699038208 |