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Titel |
An analysis of Pc3 and Pc4 pulsations at Terra Nova Bay (Antarctica) |
VerfasserIn |
U. Villante, M. Vellante, G. Sanctis |
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. 11 ; Nr. 18, no. 11, S.1412-1421 |
Datensatznummer |
250014090
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Publikation (Nr.) |
copernicus.org/angeo-18-1412-2000.pdf |
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Zusammenfassung |
We conducted a statistical analysis of the
physical characteristics of the micropulsation activity (Pc3 and Pc4 range)
detected, during the austral summer 1994–95, at Terra Nova Bay (Antarctica,
corrected latitude 80.0°S), a station which is few degrees poleward of those
where most of the Antarctic measurements in these frequency ranges have been
performed. The emerging overview suggests that the correspondence between the
pulsation power and the external parameters (solar wind speed, interplanetary
magnetic field magnitude and orientation) is significantly stronger than at
somewhat lower latitudes. The day-to-day power variability was found to be
strictly related to the general level of the geomagnetic activity, and the power
level sharply maximizes at local magnetic noon. In the Pc4 range peaks of
correlation with the SW speed are found in the dawn and dusk sides of the
Earth's magnetosphere and the daily variation of the polarization pattern is
closely consistent with that found at auroral latitudes and at lower
frequencies. In the Pc3 range the correlation coefficient between the pulsation
power and the SW speed has maximum values in the local morning, and the
frequency of selected events reveals a strong IMF control during closed
magnetospheric conditions. The local time dependence of the correlation
coefficient between the pulsation power and the cone angle reveals an additional
control by the IMF orientation, which becomes more explicit around local noon.
Key words: Magnetospheric physics (magnetopause, cusp,
and boundary layers) |
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