Abstract
Abstract. Pc3 geomagnetic field fluctuations detected at low latitude (L'Aquila, Italy) during the passage of a high velocity solar wind stream, characterized by variable interplanetary magnetic field conditions, are analyzed. Higher frequency resonant fluctuations and lower frequency phenomena are simultaneously observed; the intermittent appearance and the variable frequency of the longer period modes can be well interpreted in terms of the variable IMF elements; moreover their polarization characteristics are consistent with an origin related to external waves propagating in antisunward direction. A comparison with simultaneous observations performed at Terra Nova Bay (Antarctica) provides additional evidence for a clear relationship between the IMF and Pc3 pulsations also at very high latitudes.Key words. Magnetospheric physics (MHD waves and instabilities; solar wind · magnetosphere interactions)
Highlights
The physical characteristics of geomagnetic micropulsations and their association with interplanetary and magnetospheric structures are important tools for a better understanding of the primary sources of such phenomena
At lower latitudes (L = 1.6) Villante et al (1992) examined three dierent days in 1985 during which the solar wind velocity remained high and approximately constant and showed that the ground power of Pc3 pulsations was clearly switched by variations of the cone angle
To better analyze the correspondence between the cone angle and the pulsation power, we examined the behavior of the correlation coecient r between the logarithm of ground Pc3 power and cos(hXB) for dierent delay times: the results of our analysis (Fig. 2) show that the best correspondence is obtained during magnetic daytime hours at both stations for a delay time of the order of 10 min
Summary
The physical characteristics of geomagnetic micropulsations and their association with interplanetary and magnetospheric structures are important tools for a better understanding of the primary sources of such phenomena. At lower latitudes (L = 1.6) Villante et al (1992) examined three dierent days in 1985 during which the solar wind velocity remained high and approximately constant and showed that the ground power of Pc3 pulsations was clearly switched by variations of the cone angle.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
