Magnetosphere-ionosphere coupling during periods of extended high auroral activity: a case study
Item
Title (Dublin Core)
Magnetosphere-ionosphere coupling during periods of extended high auroral activity: a case study
Description (Dublin Core)
Results are presented from a case study of a plasma boundary
crossing by the Cluster spacecraft during an extended period of
high auroral activity. The boundary between the magnetotail lobe
region of the Southern Hemisphere and the plasma sheet boundary
layer, was characterized by intense electric and magnetic field
variations, structured upward accelerated ion beams, narrow-scale
large field-aligned Poynting fluxes directed upward away from the
ionosphere, and a relatively sharp plasma density gradient.
<br><br>
The observations are shown to be consistent with the concept of a
multi-layered boundary with temporal and/or spatial variations in
the different layers. H<sup>+</sup> and O<sup>+</sup> ion beams are seen to be
accelerated upwards both by means of a field-aligned electric
field and by magnetic pumping caused by large-amplitude and
low-frequency electric field fluctuations. The peak energy of the
ion beams may here be used as a diagnostic tool for the temporal
evolution of the spatial structures, since the temporal changes
occur on a time-scale shorter than the times-of-flight of the
detected ion species.
<br><br>
The case study also shows the boundary region to be mainly
characterized by a coupling of the detected potential structures
to the low ionosphere during the extended period of high auroral
activity, as indicated by the intense field-aligned Poynting
fluxes directed upward away from the ionosphere.
crossing by the Cluster spacecraft during an extended period of
high auroral activity. The boundary between the magnetotail lobe
region of the Southern Hemisphere and the plasma sheet boundary
layer, was characterized by intense electric and magnetic field
variations, structured upward accelerated ion beams, narrow-scale
large field-aligned Poynting fluxes directed upward away from the
ionosphere, and a relatively sharp plasma density gradient.
<br><br>
The observations are shown to be consistent with the concept of a
multi-layered boundary with temporal and/or spatial variations in
the different layers. H<sup>+</sup> and O<sup>+</sup> ion beams are seen to be
accelerated upwards both by means of a field-aligned electric
field and by magnetic pumping caused by large-amplitude and
low-frequency electric field fluctuations. The peak energy of the
ion beams may here be used as a diagnostic tool for the temporal
evolution of the spatial structures, since the temporal changes
occur on a time-scale shorter than the times-of-flight of the
detected ion species.
<br><br>
The case study also shows the boundary region to be mainly
characterized by a coupling of the detected potential structures
to the low ionosphere during the extended period of high auroral
activity, as indicated by the intense field-aligned Poynting
fluxes directed upward away from the ionosphere.
Creator (Dublin Core)
S. Liléo
G. T. Marklund
T. Karlsson
T. Johansson
P.-A. Lindqvist
A. Marchaudon
A. Fazakerley
C. Mouikis
L. M. Kistler
Subject (Dublin Core)
Science
Q
Physics
QC1-999
Geophysics. Cosmic physics
QC801-809
Publisher (Dublin Core)
Copernicus Publications
Date (Dublin Core)
2008-03-01T00:00:00Z
Type (Dublin Core)
article
Identifier (Dublin Core)
10.5194/angeo-26-583-2008
0992-7689
1432-0576
https://doaj.org/article/3fbcae6372ab4e43afafcaf2214a2c0e
Source (Dublin Core)
Annales Geophysicae, Vol 26, Pp 583-591 (2008)
Language (Dublin Core)
EN
Relation (Dublin Core)
https://www.ann-geophys.net/26/583/2008/angeo-26-583-2008.pdf
https://doaj.org/toc/0992-7689
https://doaj.org/toc/1432-0576
Provenance (Dublin Core)
Journal Licence: CC BY