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Coordinated Cluster/Double Star and ground-based observations of dayside reconnection signatures on 11 February 2004

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journal contribution
posted on 24.10.2012, 09:21 by Q-H. Zhang, R-Y. Liu, H-G. Yang, H-Q. Hu, B-C. Zhang, Z-J. Hu, M. W. Dunlop, I. W. McCrea, S. R. Crothers, M. Lester, Y. V. Bogdanova, La Hoz C., C. P. Nielsen
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.

Funding

This work is supported by the National Natural Science Foundation of China (grant No. 41104091, 41031064, 40890164, 40974083), the Natural Science Foundation of Shanghai, China (grant No. 11ZR1441200), the Youth Scientific and Technological Innovation Foundation, Polar Research Institute of China (No. JDQ201001) and Ocean Public Welfare Scientific Research Project, State Oceanic Administration People’s Republic of China (No. 201005017). M. W. Dunlop is partly supported by Chinese Academy of Sciences (CAS) visiting Professorship for senior international scientists (Grant No. 2009S1-54). M. Lester is supported by STFC grant ST/H002480/1.

History

Citation

Annales Geophysicae, 2011, 29 (10), pp. 1827-1847

Published in

Annales Geophysicae

Publisher

European Geosciences Union (EGU), Copernicus Publications, Springer Verlag

issn

0992-7689

eissn

1432-0576

Copyright date

2011

Available date

24/10/2012

Publisher version

http://www.ann-geophys.net/29/1827/2011/angeo-29-1827-2011.html

Language

en

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