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Titel |
Coordinated Cluster/Double Star and ground-based observations of dayside reconnection signatures on 11 February 2004 |
VerfasserIn |
Q.-H. Zhang, M. W. Dunlop, R.-Y. Liu, H.-G. Yang, H.-Q. Hu, B.-C. Zhang, Mark Lester, Y. V. Bogdanova, I. W. McCrea, Z.-J. Hu, S. R. Crothers, C. Hoz, C. P. Nielsen |
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 ; 29, no. 10 ; Nr. 29, no. 10 (2011-10-24), S.1827-1847 |
Datensatznummer |
250017109
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Publikation (Nr.) |
copernicus.org/angeo-29-1827-2011.pdf |
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Zusammenfassung |
A number of flux transfer events (FTEs) were observed between 09:00 and
12:00 UT on 11 February 2004, during southward and dawnward IMF, while the
Cluster spacecraft array moved outbound through the northern, high-altitude
cusp and dayside high-latitude boundary layer, and the Double Star TC-1
spacecraft was crossing the dayside low-latitude magnetopause into the
magnetosheath south of the ecliptic plane. The Cluster array grazed the
equatorial cusp boundary, observing reconnection-like mixing of
magnetosheath and magnetospheric plasma populations. In an adjacent
interval, TC-1 sampled a series of sometimes none standard FTEs, but also
with mixed magnetosheath and magnetospheric plasma populations, near the
magnetopause crossing and later showed additional (possibly turbulent)
activity not characteristic of FTEs when it was situated deeper in the
magnetosheath. The motion of these FTEs are analyzed in some detail to
compare to simultaneous, poleward-moving plasma concentration enhancements
recorded by EISCAT Svalbard Radar (ESR) and "poleward-moving radar auroral
forms" (PMRAFs) on the CUTLASS Finland and Kerguelen Super Dual Auroral
Radar Network (SuperDARN) radar measurements. Conjugate SuperDARN
observations show a predominantly two-cell convection pattern in the
Northern and Southern Hemispheres. The results are consistent with the
expected motion of reconnected magnetic flux tubes, arising from a
predominantly sub-solar reconnection site. Here, we are able to track north
and south in closely adjacent intervals as well as to map to the
corresponding ionospheric footprints of the implied flux tubes and
demonstrate these are temporally correlated with clear ionospheric velocity
enhancements, having northward (southward) and eastward (westward) convected
flow components in the Northern (Southern) Hemisphere. The durations of
these enhancements might imply that the evolution time of the FTEs is about
18–22 min from their origin on magnetopause (at reconnection site) to
their addition to the magnetotail lobe. However, the ionospheric response
time in the Northern Hemisphere is about 2–4 min longer than the
response time in the Southern Hemisphere. |
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