Pc3 pulsations during variable IMF conditions

[摘要] Pc3 geomagnetic field fluctuations detectedat low latitude (L'Aquila, Italy) during the passage of a high velocity solarwind stream, characterized by variable interplanetary magnetic field conditions,are analyzed. Higher frequency resonant fluctuations and lower frequencyphenomena are simultaneously observed; the intermittent appearance and thevariable frequency of the longer period modes can be well interpreted in termsof the variable IMF elements; moreover their polarization characteristics areconsistent with an origin related to external waves propagating in antisunwarddirection. A comparison with simultaneous observations performed at Terra NovaBay (Antarctica) provides additional evidence for a clear relationship betweenthe IMF and Pc3 pulsations also at very high latitudes.

Key words. Magnetospheric physics (MHD waves andinstabilities; solar wind · magnetosphere interactions)

[学科分类] 地球科学(综合)