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| Titel |
Observations of ionospheric flows and particle precipitation following a Sudden Commencement |
| VerfasserIn |
E. Nielsen, F. Honary |
| 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 ; 18, no. 8 ; Nr. 18, no. 8, S.908-917 |
| Datensatznummer |
250014042
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| Publikation (Nr.) |
 copernicus.org/angeo-18-908-2000.pdf |
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| Zusammenfassung |
On May 4, 1998, at 0227 UT an interplanetary
shock crossed the WIND spacecraft, and half an hour later a Sudden Commencement
occurred. Coinciding with the Sudden Commencement a rapid intensification of the
flux of particle precipitation into the ionosphere was observed. Evidence is
presented that the ionospheric electric fields were influenced by the associated
dynamic variations of the ionospheric conductivities. Following the initial
phase the ionospheric flow speeds increased rapidly over the next 20 min to more
than 2000 m/s, in agreement with an increased effective coupling of the solar
wind energy to the magnetosphere following the interplanetary shock that caused
the Sudden Commencement. These strong flows were meandering in latitude, a type
of plasma flow modulation that has been reported before to occur during Omega
band events: a string of alternating field-aligned currents propagating
eastward. The riometer absorption was found to be at a minimum in regions
associated with outward directed field aligned currents. The riometer absorption
regions (the regions of particle precipitation) were drifting
with E × B drift speed of the ionospheric electrons.
Key words: Interplanetary physics (interplanetary
shocks) - Ionosphere (electric fields and currents) - Magnetospheric physics
(energetic particles, precipitating) |
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