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| Titel |
First simultaneous observations of flux transfer events at the high-latitude magnetopause by the Cluster spacecraft and pulsed radar signatures in the conjugate ionosphere by the CUTLASS and EISCAT radars |
| VerfasserIn |
J. A. Wild, S. W. H. Cowley, J. A. Davies, H. Khan, Mark Lester, S. E. Milan, G. Provan, T. K. Yeoman, A. Balogh, M. W. Dunlop, K.-H. Fornacon, E. Georgescu |
| 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 ; 19, no. 10/12 ; Nr. 19, no. 10/12, S.1491-1508 |
| Datensatznummer |
250014130
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| Publikation (Nr.) |
 copernicus.org/angeo-19-1491-2001.pdf |
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| Zusammenfassung |
Cluster magnetic field
data are studied during an outbound pass through the post-noon high-latitude
magnetopause region on 14 February 2001. The onset of several minute
perturbations in the magnetospheric field was observed in conjunction with a
southward turn of the interplanetary magnetic field observed upstream by the
ACE spacecraft and lagged to the subsolar magnetopause. These perturbations
culminated in the observation of four clear magnetospheric flux transfer events
(FTEs) adjacent to the magnetopause, together with a highly-structured
magnetopause boundary layer containing related field features. Furthermore,
clear FTEs were observed later in the magnetosheath. The magnetospheric FTEs
were of essentially the same form as the original "flux erosion
events" observed in HEOS-2 data at a similar location and under similar
interplanetary conditions by Haerendel et al. (1978). We show that the nature
of the magnetic perturbations in these events is consistent with the formation
of open flux tubes connected to the northern polar ionosphere via pulsed
reconnection in the dusk sector magnetopause. The magnetic footprint of the
Cluster spacecraft during the boundary passage is shown to map centrally within
the fields-of-view of the CUTLASS SuperDARN radars, and to pass across the
field-aligned beam of the EISCAT Svalbard radar (ESR) system. It is shown that
both the ionospheric flow and the backscatter power in the CUTLASS data pulse
are in synchrony with the magnetospheric FTEs and boundary layer structures at
the latitude of the Cluster footprint. These flow and power features are
subsequently found to propagate poleward, forming classic "pulsed
ionospheric flow" and "poleward-moving radar auroral form"
structures at higher latitudes. The combined Cluster-CUTLASS observations thus
represent a direct demonstration of the coupling of momentum and energy into
the magnetosphere-ionosphere system via pulsed magnetopause reconnection. The
ESR observations also reveal the nature of the structured and variable polar
ionosphere produced by the structured and time-varying precipitation and flow.
Key words. Ionosphere (auroral
ionosphere) Magentospheric physics (magnetopause, cusp and boundary layers;
magnetosphere-ionosphere interactions) |
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