 |
| Titel |
Propagation of low frequency geomagnetic field fluctuations in Antarctica: comparison between two polar cap stations |
| VerfasserIn |
L. Santarelli, S. Lepidi, L. Cafarella |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 25, no. 11 ; Nr. 25, no. 11 (2007-11-29), S.2405-2412 |
| Datensatznummer |
250015949
|
| Publikation (Nr.) |
 copernicus.org/angeo-25-2405-2007.pdf |
|
|
|
|
|
| Zusammenfassung |
We conduct a statistical analysis of the coherence and phase difference of
low frequency geomagnetic fluctuations between two Antarctic stations, Mario
Zucchelli Station (geographic coordinates: 74.7° S, 164.1° E;
corrected geomagnetic coordinates: 80.0° S, 307.7° E) and Scott Base
(geographic coordinates: 77.8° S 166.8° E; corrected geomagnetic
coordinates: 80.0° S 326.5° E), both located in the polar cap. Due to
the relative position of the stations, whose displacement is essentially
along a geomagnetic parallel, the phase difference analysis allows to
determine the direction of azimuthal propagation of geomagnetic
fluctuations. The results show that coherent fluctuations are essentially
detectable around local geomagnetic midnight and, in a minor extent, around
noon; moreover, the phase difference reverses in the night time hours,
indicating a propagation direction away from midnight, and also around local
geomagnetic noon, indicating a propagation direction away from the subsolar
point. The nigh time phase reversal is more clear for southward
interplanetary magnetic field conditions, suggesting a relation with
substorm activity.
The introduction, in this analysis, of the Interplanetary Magnetic Field
conditions, gave interesting results, indicating a relation with substorm
activity during nighttime hours.
We also conducted a study of three individual pulsation events in order to
find a correspondence with the statistical behaviour. In particular, a
peculiar event, characterized by quiet magnetospheric and northward
interplanetary magnetic field conditions, shows a clear example of waves
propagating away from the local geomagnetic noon; two more events, occurring
during southward interplanetary magnetic field conditions, in one case even
during a moderate storm, show waves propagating away from the local
geomagnetic midnight. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|