Variations of auroral hydrogen emission near substorm onset

The results of coordinated optical ground-based observations of the auroral substorm on 26 March 2004 in the Kola Peninsula are described. Imaging spectrograph data with high spectral and temporal resolution recorded the Doppler profile of the Hα hydrogen emission; this allows us to estimate the ave...

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Published in:Annales Geophysicae
Main Authors: Borovkov, L. P., Kozelov, B. V., Yevlashin, L. S., Chernouss, S. A.
Format: Text
Language:English
Published: 2018
Subjects:
Online Access:https://doi.org/10.5194/angeo-23-1623-2005
https://angeo.copernicus.org/articles/23/1623/2005/
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spelling ftcopernicus:oai:publications.copernicus.org:angeo35611 2023-05-15T17:05:02+02:00 Variations of auroral hydrogen emission near substorm onset Borovkov, L. P. Kozelov, B. V. Yevlashin, L. S. Chernouss, S. A. 2018-09-27 application/pdf https://doi.org/10.5194/angeo-23-1623-2005 https://angeo.copernicus.org/articles/23/1623/2005/ eng eng doi:10.5194/angeo-23-1623-2005 https://angeo.copernicus.org/articles/23/1623/2005/ eISSN: 1432-0576 Text 2018 ftcopernicus https://doi.org/10.5194/angeo-23-1623-2005 2020-07-20T16:27:25Z The results of coordinated optical ground-based observations of the auroral substorm on 26 March 2004 in the Kola Peninsula are described. Imaging spectrograph data with high spectral and temporal resolution recorded the Doppler profile of the Hα hydrogen emission; this allows us to estimate the average energy of precipitating protons and the emission intensity of the hydrogen Balmer line. Two different populations of precipitating protons were observed during an auroral substorm. The first of these is associated with a diffuse hydrogen emission that is usually observed in the evening sector of the auroral oval and located equatorward of the discrete electron arcs associated with substorm onset. The average energy of the protons during this precipitation was ~20–35 keV, and the energy flux was ~3x10 –4 Joule/m 2 s. The second proton population was observed 1–2min after the breakup during 4–5min of the expansion phase of substorm into the zone of bright, discrete auroral structures (N-S arcs). The average energy of the protons in this population was ~60 keV, and the energy flux was ~2.2x10 –3 Joule/m 2 s. The observed spatial structure of hydrogen emission is additional evidence of the higher energy of precipitated protons in the second population, relative to the protons in the diffuse aurora. We believe that the most probable mechanism of precipitation of the second population protons was pitch-angle scattering of particles due to non-adiabatic motion in the region of local dipolarization near the equatorial plane. Keywords. Auroral ionosphere; Particle precipitation; Storms and substorms Text kola peninsula Copernicus Publications: E-Journals Kola Peninsula Annales Geophysicae 23 5 1623 1635
institution Open Polar
collection Copernicus Publications: E-Journals
op_collection_id ftcopernicus
language English
description The results of coordinated optical ground-based observations of the auroral substorm on 26 March 2004 in the Kola Peninsula are described. Imaging spectrograph data with high spectral and temporal resolution recorded the Doppler profile of the Hα hydrogen emission; this allows us to estimate the average energy of precipitating protons and the emission intensity of the hydrogen Balmer line. Two different populations of precipitating protons were observed during an auroral substorm. The first of these is associated with a diffuse hydrogen emission that is usually observed in the evening sector of the auroral oval and located equatorward of the discrete electron arcs associated with substorm onset. The average energy of the protons during this precipitation was ~20–35 keV, and the energy flux was ~3x10 –4 Joule/m 2 s. The second proton population was observed 1–2min after the breakup during 4–5min of the expansion phase of substorm into the zone of bright, discrete auroral structures (N-S arcs). The average energy of the protons in this population was ~60 keV, and the energy flux was ~2.2x10 –3 Joule/m 2 s. The observed spatial structure of hydrogen emission is additional evidence of the higher energy of precipitated protons in the second population, relative to the protons in the diffuse aurora. We believe that the most probable mechanism of precipitation of the second population protons was pitch-angle scattering of particles due to non-adiabatic motion in the region of local dipolarization near the equatorial plane. Keywords. Auroral ionosphere; Particle precipitation; Storms and substorms
format Text
author Borovkov, L. P.
Kozelov, B. V.
Yevlashin, L. S.
Chernouss, S. A.
spellingShingle Borovkov, L. P.
Kozelov, B. V.
Yevlashin, L. S.
Chernouss, S. A.
Variations of auroral hydrogen emission near substorm onset
author_facet Borovkov, L. P.
Kozelov, B. V.
Yevlashin, L. S.
Chernouss, S. A.
author_sort Borovkov, L. P.
title Variations of auroral hydrogen emission near substorm onset
title_short Variations of auroral hydrogen emission near substorm onset
title_full Variations of auroral hydrogen emission near substorm onset
title_fullStr Variations of auroral hydrogen emission near substorm onset
title_full_unstemmed Variations of auroral hydrogen emission near substorm onset
title_sort variations of auroral hydrogen emission near substorm onset
publishDate 2018
url https://doi.org/10.5194/angeo-23-1623-2005
https://angeo.copernicus.org/articles/23/1623/2005/
geographic Kola Peninsula
geographic_facet Kola Peninsula
genre kola peninsula
genre_facet kola peninsula
op_source eISSN: 1432-0576
op_relation doi:10.5194/angeo-23-1623-2005
https://angeo.copernicus.org/articles/23/1623/2005/
op_doi https://doi.org/10.5194/angeo-23-1623-2005
container_title Annales Geophysicae
container_volume 23
container_issue 5
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