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Titel |
Are dayside long-period pulsations related to the cusp? |
VerfasserIn |
V. Pilipenko, V. Belakhovsky, M. J. Engebretson, A. Kozlovsky, T. Yeoman |
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 ; 33, no. 3 ; Nr. 33, no. 3 (2015-03-24), S.395-404 |
Datensatznummer |
250121182
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Publikation (Nr.) |
copernicus.org/angeo-33-395-2015.pdf |
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Zusammenfassung |
We compare simultaneous observations of long-period ultra-low-frequency (ULF) wave activity from a
Svalbard/IMAGE fluxgate magnetometer latitudinal profile covering the
expected cusp geomagnetic latitudes. Irregular Pulsations at Cusp Latitudes
(IPCL) and narrowband Pc5 waves are found to be a ubiquitous element of ULF
activity in the dayside high-latitude region. To identify the ionospheric
projections of the cusp, we use the width of return signal of the Super Dual Auroral Radar Network
(SuperDARN)
radar covering the Svalbard archipelago, predictions of empirical cusp
models, augmented whenever possible by Defense Meteorological Satellite Program (DMSP) identification of
magnetospheric boundary domains. The meridional spatial structure of
broadband dayside Pc5–6 pulsation spectral power has been found to have a
localized latitudinal peak, not under the cusp proper as was previously
thought, but several degrees southward from the equatorward cusp boundary.
The earlier claims of the dayside monochromatic Pc5 wave association with the
open–closed boundary also seems doubtful. Transient currents producing
broadband Pc5–6 probably originate at the low-latitude boundary layer/central plasma sheet (LLBL/CPS) interface, though such
identification with available DMSP data is not very precise. The occurrence
of broadband Pc5–6 pulsations in the dayside boundary layers is a challenge
to modelers because so far their mechanism has not been firmly identified. |
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