Study of auroral forms and electron precipitation with the IRIS, DASI and EISCAT systems
International audience Simultaneous observations with the IRIS, DASI and EISCAT systems are employed in the study of the spatial distribution and temporal evolution of auroral forms and precipitation regions during substorm activity. The evolution of the spectrum of precipitating electrons above Tro...
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ftccsdartic:oai:HAL:hal-00317130v1 2023-11-12T04:16:35+01:00 Study of auroral forms and electron precipitation with the IRIS, DASI and EISCAT systems del Pozo, C. F. Honary, F. Stamatiou, N. Kosch, M. J. Department of Communication Systems 2002 https://hal.science/hal-00317130 https://hal.science/hal-00317130/document https://hal.science/hal-00317130/file/angeo-20-1361-2002.pdf en eng HAL CCSD European Geosciences Union hal-00317130 https://hal.science/hal-00317130 https://hal.science/hal-00317130/document https://hal.science/hal-00317130/file/angeo-20-1361-2002.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00317130 Annales Geophysicae, 2002, 20 (9), pp.1361-1375 [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 2002 ftccsdartic 2023-10-21T23:07:48Z International audience Simultaneous observations with the IRIS, DASI and EISCAT systems are employed in the study of the spatial distribution and temporal evolution of auroral forms and precipitation regions during substorm activity. The evolution of the spectrum of precipitating electrons above Tromsø during the various phases of substorms is discussed. The flux-energy spectrum in the 1?320 keV range is derived from EISCAT electron density profiles in the 70?140 km altitude range. At the late growth phase the precipitation flux at the higher energies increases faster than at the lower energies. The flux is always greater in the lower energy side of the spectrum and reaches a maximum a few minutes after substorm onset, then it decays while the spectrum narrows. The systematic analysis of 2-D structures corresponding with well-defined optical and absorption features is also discussed. The orientation, characteristic lengths (elongation and width) and the gravity centre of these spatial features are determined. The statistical analysis of centre position and the sizes of the corresponding signatures is presented. When substorm onset falls within the common field of view, there is a close correspondence between the optical and the absorption signatures of the auroral forms, as well as in their over-all north-south motion characteristic of the various phases of the substorm. Optical signatures of arcs are more evenly distributed in space, being narrower and elongated along the L-shells, while the absorption regions appear more structured and patchy, although generally following the arcs' shape and alignment. Cross-correlation of the time series of maximum absorption and maximum green-line emission is very high and seems to show a systematic delay of absorption relative to optical emission. Time delays are generally larger for disturbed conditions (40 to 60 s) than for moderately active conditions (10 to 20 s). Article in Journal/Newspaper EISCAT Tromsø Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Narrows The ENVELOPE(-67.167,-67.167,-67.617,-67.617) Tromsø |
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Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
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 del Pozo, C. F. Honary, F. Stamatiou, N. Kosch, M. J. Study of auroral forms and electron precipitation with the IRIS, DASI and EISCAT systems |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience Simultaneous observations with the IRIS, DASI and EISCAT systems are employed in the study of the spatial distribution and temporal evolution of auroral forms and precipitation regions during substorm activity. The evolution of the spectrum of precipitating electrons above Tromsø during the various phases of substorms is discussed. The flux-energy spectrum in the 1?320 keV range is derived from EISCAT electron density profiles in the 70?140 km altitude range. At the late growth phase the precipitation flux at the higher energies increases faster than at the lower energies. The flux is always greater in the lower energy side of the spectrum and reaches a maximum a few minutes after substorm onset, then it decays while the spectrum narrows. The systematic analysis of 2-D structures corresponding with well-defined optical and absorption features is also discussed. The orientation, characteristic lengths (elongation and width) and the gravity centre of these spatial features are determined. The statistical analysis of centre position and the sizes of the corresponding signatures is presented. When substorm onset falls within the common field of view, there is a close correspondence between the optical and the absorption signatures of the auroral forms, as well as in their over-all north-south motion characteristic of the various phases of the substorm. Optical signatures of arcs are more evenly distributed in space, being narrower and elongated along the L-shells, while the absorption regions appear more structured and patchy, although generally following the arcs' shape and alignment. Cross-correlation of the time series of maximum absorption and maximum green-line emission is very high and seems to show a systematic delay of absorption relative to optical emission. Time delays are generally larger for disturbed conditions (40 to 60 s) than for moderately active conditions (10 to 20 s). |
author2 |
Department of Communication Systems |
format |
Article in Journal/Newspaper |
author |
del Pozo, C. F. Honary, F. Stamatiou, N. Kosch, M. J. |
author_facet |
del Pozo, C. F. Honary, F. Stamatiou, N. Kosch, M. J. |
author_sort |
del Pozo, C. F. |
title |
Study of auroral forms and electron precipitation with the IRIS, DASI and EISCAT systems |
title_short |
Study of auroral forms and electron precipitation with the IRIS, DASI and EISCAT systems |
title_full |
Study of auroral forms and electron precipitation with the IRIS, DASI and EISCAT systems |
title_fullStr |
Study of auroral forms and electron precipitation with the IRIS, DASI and EISCAT systems |
title_full_unstemmed |
Study of auroral forms and electron precipitation with the IRIS, DASI and EISCAT systems |
title_sort |
study of auroral forms and electron precipitation with the iris, dasi and eiscat systems |
publisher |
HAL CCSD |
publishDate |
2002 |
url |
https://hal.science/hal-00317130 https://hal.science/hal-00317130/document https://hal.science/hal-00317130/file/angeo-20-1361-2002.pdf |
long_lat |
ENVELOPE(-67.167,-67.167,-67.617,-67.617) |
geographic |
Narrows The Tromsø |
geographic_facet |
Narrows The Tromsø |
genre |
EISCAT Tromsø |
genre_facet |
EISCAT Tromsø |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00317130 Annales Geophysicae, 2002, 20 (9), pp.1361-1375 |
op_relation |
hal-00317130 https://hal.science/hal-00317130 https://hal.science/hal-00317130/document https://hal.science/hal-00317130/file/angeo-20-1361-2002.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782333648984342528 |