Particle precipitations during NEIAL events: simultaneous ground based observations at Svalbard
International audience In this paper we present Naturally Enhanced Ion Acoustic Lines (NEIALs) observed with the EISCAT Svalbard Radar (ESR). For the first time, long sequences of NEIALs are recorded, with more than 50 events within an hour, ranging from 6.4 to 140 s in duration. The events took pla...
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ftccsdartic:oai:HAL:hal-00318336v1 2023-11-12T04:16:37+01:00 Particle precipitations during NEIAL events: simultaneous ground based observations at Svalbard Lunde, J. Gustavsson, B. Løvhaug, U. P. Lorentzen, D. A. Ogawa, Y. Department of Physics Okayama University Geophysics Department The University Centre in Svalbard (UNIS) National Institute of Polar Research Tokyo (NiPR) 2007-06-29 https://hal.science/hal-00318336 https://hal.science/hal-00318336/document https://hal.science/hal-00318336/file/angeo-25-1323-2007.pdf en eng HAL CCSD European Geosciences Union hal-00318336 https://hal.science/hal-00318336 https://hal.science/hal-00318336/document https://hal.science/hal-00318336/file/angeo-25-1323-2007.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00318336 Annales Geophysicae, 2007, 25 (6), pp.1323-1336 [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 2007 ftccsdartic 2023-10-21T23:06:37Z International audience In this paper we present Naturally Enhanced Ion Acoustic Lines (NEIALs) observed with the EISCAT Svalbard Radar (ESR). For the first time, long sequences of NEIALs are recorded, with more than 50 events within an hour, ranging from 6.4 to 140 s in duration. The events took place from ~08:45 to 10:00 UT, 22 January 2004. We combine ESR data with observations of optical aurora by a meridian scanning photometer at wavelengths 557.7, 630.0, 427.8, and 844.6 nm, as well as records from a magnetometer and an imaging riometer. The large numbers of observed NEIALs together with these additional observations, enable us to characterise the particle precipitation during the NEIAL events. We find that the intensities in all optical lines studied must be above a certain level for the NEIALs to appear. We also find that the soft particle precipitation is associated with the down-shifted shoulder in the incoherent scatter spectrum, and that harder precipitation may play a role in the enhancement of the up-shifted shoulder. The minimum energy flux during NEIAL events found in this study was ~3.5 mW/m 2 and minimum characteristic energy around 50 eV. Article in Journal/Newspaper EISCAT Svalbard Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Svalbard |
institution |
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 Lunde, J. Gustavsson, B. Løvhaug, U. P. Lorentzen, D. A. Ogawa, Y. Particle precipitations during NEIAL events: simultaneous ground based observations at Svalbard |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience In this paper we present Naturally Enhanced Ion Acoustic Lines (NEIALs) observed with the EISCAT Svalbard Radar (ESR). For the first time, long sequences of NEIALs are recorded, with more than 50 events within an hour, ranging from 6.4 to 140 s in duration. The events took place from ~08:45 to 10:00 UT, 22 January 2004. We combine ESR data with observations of optical aurora by a meridian scanning photometer at wavelengths 557.7, 630.0, 427.8, and 844.6 nm, as well as records from a magnetometer and an imaging riometer. The large numbers of observed NEIALs together with these additional observations, enable us to characterise the particle precipitation during the NEIAL events. We find that the intensities in all optical lines studied must be above a certain level for the NEIALs to appear. We also find that the soft particle precipitation is associated with the down-shifted shoulder in the incoherent scatter spectrum, and that harder precipitation may play a role in the enhancement of the up-shifted shoulder. The minimum energy flux during NEIAL events found in this study was ~3.5 mW/m 2 and minimum characteristic energy around 50 eV. |
author2 |
Department of Physics Okayama University Geophysics Department The University Centre in Svalbard (UNIS) National Institute of Polar Research Tokyo (NiPR) |
format |
Article in Journal/Newspaper |
author |
Lunde, J. Gustavsson, B. Løvhaug, U. P. Lorentzen, D. A. Ogawa, Y. |
author_facet |
Lunde, J. Gustavsson, B. Løvhaug, U. P. Lorentzen, D. A. Ogawa, Y. |
author_sort |
Lunde, J. |
title |
Particle precipitations during NEIAL events: simultaneous ground based observations at Svalbard |
title_short |
Particle precipitations during NEIAL events: simultaneous ground based observations at Svalbard |
title_full |
Particle precipitations during NEIAL events: simultaneous ground based observations at Svalbard |
title_fullStr |
Particle precipitations during NEIAL events: simultaneous ground based observations at Svalbard |
title_full_unstemmed |
Particle precipitations during NEIAL events: simultaneous ground based observations at Svalbard |
title_sort |
particle precipitations during neial events: simultaneous ground based observations at svalbard |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-00318336 https://hal.science/hal-00318336/document https://hal.science/hal-00318336/file/angeo-25-1323-2007.pdf |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
EISCAT Svalbard |
genre_facet |
EISCAT Svalbard |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00318336 Annales Geophysicae, 2007, 25 (6), pp.1323-1336 |
op_relation |
hal-00318336 https://hal.science/hal-00318336 https://hal.science/hal-00318336/document https://hal.science/hal-00318336/file/angeo-25-1323-2007.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782333699242590208 |