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| Titel |
Subauroral polarization streams: observations with the Hokkaido and King Salmon SuperDARN radars and modeling |
| VerfasserIn |
A. Koustov, N. Nishitani, Y. Ebihara, T. Kikuchi, M. R. Hairston, D. Andre |
| 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 ; 26, no. 11 ; Nr. 26, no. 11 (2008-10-21), S.3317-3327 |
| Datensatznummer |
250016273
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| Publikation (Nr.) |
 copernicus.org/angeo-26-3317-2008.pdf |
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| Zusammenfassung |
| The newly installed SuperDARN Hokkaido HF radar monitors ionospheric plasma
flow between magnetic latitudes of 45° and 65° and thus has a
great potential for studies of subauroral polarization streams (SAPS) in
combination with another SuperDARN radar located at King Salmon, Alaska as
well as the DMSP satellites and ground-based instruments in the Alaskan
sector of the Arctic. Preliminary survey shows that although SAPS are often
detected with the Hokkaido radar, their velocities are rather low, to the
order of 150 m/s in its most suitable central beams. In this study,
observations of unusually fast Hokkaido flows of up to 800 m/s are presented.
The event of 1 April 2007 is investigated in detail. It is
shown that high-velocity echoes appear after substorm onsets over North
America with a delay of ~30 min. In terms of latitude, the velocity
peaks just outside the auroral oval; signatures of a detached polarization
jet are occasional and not pronounced. The King Salmon radar operating
concurrently detects SAPS signatures as well but at different times and
locations. Simulation with the Comprehensive Ring Current Model for the 1
April event reasonably identifies the period of fast flow occurrence but the
velocity is underestimated. The event studied suggests that
substorm-injected particle populations may intensify the pre-existing SAPS
flow and lead to a mismatch of the predictions and observations. |
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