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| Titel |
On determining the noon polar cap boundary from SuperDARN HF radar backscatter characteristics |
| VerfasserIn |
M. Pinnock, A. S. Rodger |
| 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. 12 ; Nr. 18, no. 12, S.1523-1530 |
| Datensatznummer |
250014098
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| Publikation (Nr.) |
 copernicus.org/angeo-18-1523-2000.pdf |
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| Zusammenfassung |
Previous work has shown that ionospheric HF
radar backscatter in the noon sector can be used to locate the footprint of the
magnetospheric cusp particle precipitation. This has enabled the radar data to
be used as a proxy for the location of the polar cap boundary, and hence measure
the flow of plasma across it to derive the reconnection electric field in the
ionosphere. This work used only single radar data sets with a field of view
limited to ~2 h of local time. In this case study using four of the SuperDARN
radars, we examine the boundary determined over 6 h of magnetic local time
around the noon sector and its relationship to the convection pattern. The
variation with longitude of the latitude of the radar scatter with cusp
characteristics shows a bay-like feature. It is shown that this feature is
shaped by the variation with longitude of the poleward flow component of the
ionospheric plasma and may be understood in terms of cusp ion time-of-flight
effects. Using this interpretation, we derive the time-of-flight of the cusp
ions and find that it is consistent with approximately 1 keV ions injected from
a subsolar reconnection site. A method for deriving a more accurate estimate of
the location of the open-closed field line boundary from HF radar data is
described.
Key words: Ionosphere (ionosphere–magnetosphere
interactions; plasma convection) · Magnetospheric physics (magnetopause · cusp
· and boundary layers) |
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