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| Titel |
A statistical survey of dayside pulsed ionospheric flows as seen by the CUTLASS Finland HF radar |
| VerfasserIn |
K. A. McWilliams, T. K. Yeoman, G. Provan |
| 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. 4 ; Nr. 18, no. 4, S.445-453 |
| Datensatznummer |
250013955
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| Publikation (Nr.) |
 copernicus.org/angeo-18-445-2000.pdf |
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| Zusammenfassung |
Nearly two years of 2-min resolution data and
7- to 21-s resolution data from the CUTLASS Finland HF radar have undergone
Fourier analysis in order to study statistically the occurrence rates and
repetition frequencies of pulsed ionospheric flows in the noon-sector
high-latitude ionosphere. Pulsed ionospheric flow bursts are believed to be the
ionospheric footprint of newly reconnected geomagnetic field lines, which occur
during episodes of magnetic flux transfer to the terrestrial magnetosphere -
flux transfer events or FTEs. The distribution of pulsed ionospheric flows were
found to be well grouped in the radar field of view, and to be in the vicinity
of the radar signature of the cusp footprint. Two thirds of the pulsed
ionospheric flow intervals included in the statistical study occurred when the
interplanetary magnetic field had a southward component, supporting the
hypothesis that pulsed ionospheric flows are a reconnection-related phenomenon.
The occurrence rate of the pulsed ionospheric flow fluctuation period was
independent of the radar scan mode. The statistical results obtained from the
radar data are compared to occurrence rates and repetition frequencies of FTEs
derived from spacecraft data near the magnetopause reconnection region, and to
ground-based optical measurements of poleward moving auroral forms. The
distributions obtained by the various instruments in different regions of the
magnetosphere were remarkably similar. The radar, therefore, appears to give an
unbiased sample of magnetopause activity in its routine observations of the cusp
footprint.
Key words: Magnetospheric physics
(magnetosphere-ionosphere interactions; plasma convection; solar
wind-magnetosphere interactions) |
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