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| Titel |
Pc3-4 ULF waves observed by the SuperDARN TIGER radar |
| VerfasserIn |
P. V. Ponomarenko, F. W. Menk, C. L. Waters, M. D. Sciffer |
| 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 ; 23, no. 4 ; Nr. 23, no. 4 (2005-06-03), S.1271-1280 |
| Datensatznummer |
250015222
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| Publikation (Nr.) |
 copernicus.org/angeo-23-1271-2005.pdf |
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| Zusammenfassung |
| Despite extensive research, the mechanisms for propagation of Pc3-4 energy
from the generation region at the bow shock to the high-latitude ionosphere
remain unresolved. We used high temporal (6-12s) and spatial (45km)
resolution data from the SuperDARN TIGER radar (Tasmania) to examine Pc3-4
wave signatures at the F-region heights. We focus on a case study on 28
September 2000, when large-amplitude band-limited Pc3-4 oscillations were
observed across 10-20 range gates in beam #4 (which points towards the CGM
pole) for about four hours preceding MLT noon. These waves were detected in
sea-scatter echoes reflected from the ionospheric footprint of the
plasmatrough. Nearby ground magnetometer data from Macquarie Island showed
very similar variations in both the north-south and east-west components. The
radar data revealed the occasional presence of quasi-FLR (field-line
resonance) spatial structures with frequencies much higher than those of the
local fundamental FLR modes. Detailed spectral analysis of the ionospheric
and ground data shows that these structures most probably correspond to a
3rd-harmonic, poloidal-mode FLR. Such observations suggest that compressional
Pc3-4 waves produced in the upstream solar wind travel earthward from the
magnetopause in the magnetic equatorial plane depositing energy into the
Alfvenic modes, as either forced or 3rd-harmonic FLR that reach ionospheric
heights along magnetic field lines. |
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