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| Titel |
The spatial distribution of region 2 field-aligned currents relative to subauroral polarization stream |
| VerfasserIn |
H. Wang, H. Lühr, A. Ridley, T. Huang |
| 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 ; 32, no. 5 ; Nr. 32, no. 5 (2014-05-22), S.533-542 |
| Datensatznummer |
250121060
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| Publikation (Nr.) |
 copernicus.org/angeo-32-533-2014.pdf |
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| Zusammenfassung |
| To test the current-generation model of subauroral polarization stream
(SAPS), we have investigated the relative positions of field-aligned currents
(FACs) with respect to SAPS in a statistical way by using CHAMP (CHAllenging Minisatellite Payload) and
DMSP (Defense Meteorological Satellite Program)
satellite observations as well as model simulations. Comparative studies have
been performed for consecutive CHAMP observations in different magnetic local
time (MLT) sectors with respect to SAPS. The latitude of the peak westward zonal
wind deduced from CHAMP measurements has been used to represent the location
of the SAPS peak. Both the density and the sheet current strength of R2
(region 2) FACs are enhanced when SAPS occur. Subsequently R2 FACs decay in
intensity and correspondingly the centers retreat poleward. The latitudes of
the center of the R2 FAC, small- and medium-scale FACs, and SAPS shift equatorward
with increasing MLT. The SAPS peaks are located between R2 and R1 (region 1)
FAC peaks in all MLT bins under study. The SAPS peaks are closer to R2
centers in the later MLT sectors. The peaks of small- and medium-scale FACs
are located poleward of SAPS, mainly in the upward R1 FACs region. The
upward R1 FACs are partly closed by the downward R1 FACs in the dawn–morning sector.
Based on model simulation, when R2 shifts equatorward to the subauroral region,
the plasma flow also shifts equatorward with its peak located poleward of that
of R2 FACs. Both the model and observations provide evidence that SAPS
behave as caused by a magnetospheric current source. |
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