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| Titel |
Substorm associated radar auroral surges: a statistical study and possible generation model |
| VerfasserIn |
B. A. Shand, Mark Lester, T. K. Yeoman |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 16, no. 4 ; Nr. 16, no. 4, S.441-449 |
| Datensatznummer |
250013245
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| Publikation (Nr.) |
 copernicus.org/angeo-16-441-1998.pdf |
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| Zusammenfassung |
Substorm-associated radar auroral surges
(SARAS) are a short lived (15–90 minutes) and spatially localised (~5° of
latitude) perturbation of the plasma convection pattern observed within the
auroral E-region. The understanding of such phenomena has important
ramifications for the investigation of the larger scale plasma convection and
ultimately the coupling of the solar wind, magnetosphere and ionosphere system.
A statistical investigation is undertaken of SARAS, observed by the Sweden And
Britain Radar Experiment (SABRE), in order to provide a more extensive
examination of the local time occurrence and propagation characteristics of the
events. The statistical analysis has determined a local time occurrence of
observations between 1420 MLT and 2200 MLT with a maximum occurrence centred
around 1700 MLT. The propagation velocity of the SARAS feature through the SABRE
field of view was found to be predominately L-shell aligned with a velocity
centred around 1750 m s–1 and within the range 500 m s–1
and 3500 m s–1. This comprehensive examination of the SARAS provides
the opportunity to discuss, qualitatively, a possible generation mechanism for
SARAS based on a proposed model for the production of a similar phenomenon
referred to as sub-auroral ion drifts (SAIDs). The results of the comparison
suggests that SARAS may result from a similar geophysical mechanism to that
which produces SAID events, but probably occurs at a different time in the
evolution of the event.
Key words. Substorms · Auroral surges · Plasma
con-vection · Sub-auroral ion drifts |
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