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| Titel |
A slow mode wave as a possible source of Pi 2 and associated particle precipitation: a case study |
| VerfasserIn |
O. Saka, O. Watanabe, K. Okada, D. N. Baker |
| 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 ; 17, no. 5 ; Nr. 17, no. 5, S.674-681 |
| Datensatznummer |
250013749
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| Publikation (Nr.) |
 copernicus.org/angeo-17-674-1999.pdf |
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| Zusammenfassung |
An intensification of auroral luminosity
referred to as an auroral break-up often accompanies the onset of geomagnetic
pulsation (Pi 2) at the dip-equator. One such auroral break-up occurred at 2239
UT on 16 June, 1986, being accompanied by weak substorm activity (AE~50 nT)
which was recorded in all-sky image of Syowa Station, Antarctica (66.2°S, 71.8°E
in geomagnetic coordinates). The associated Pi 2 magnetic pulsation was detected
by a fluxgate magnetometer in the afternoon sector at the dip-equator (Huancayo,
Peru; 1.44°N, 355.9° in geomagnetic coordinates; 12.1°S, 75.2°W in
geographic coordinates; L=1.00). In spite of the large separation of the
two stations in longitude and latitude, the auroral break-up and subsequent
luminosity modulation were seen to be correlated with the wave form of the
ground Pi 2 pulsation. This occurred in such a way that the luminosity maximum
was seen to occur at the phase of maximum amplitudes of Pi 2 wave form. We argue
that the observed correlation could be interpreted as indicating a Pi
2-modulation of a field-aligned acceleration of the low energy electrons that
may occur near the equator of the midnight magnetosphere.
Key words. Magnetospheric physics (auroral phenomena;
energetic particles · precipitating; MHD waves and instabilities) |
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