Abstract
Geomagnetic field fluctuations detected at L'Aquila ( L ∼ 1.6) during 1985 have been investigated on a statistical basis in the range of frequencies 7.8–234 mHz (Pc2, Pc3 and Pc4). The most significant events have been selected by means of a comparison between dynamic power spectra and the background spectrum. Dayside events, which perturb mainly the North-South component, tend to occur in two separate ranges, namely P 1 = 25 ± 5 s, and P 2 = 13 ± 2 s. The morphological differences between these groups of oscillations appear consistent with a wide source spectrum peaked at P 1 (possibly upstream waves generated in the solar wind foreshock region) and a resonant mechanism at P 2 which might correspond to the fundamental eigenperiod of the local field-line. Night-time events show all the characteristics of Pi2 pulsations and no evidence for field-line resonance phenomena is supported by the experimental observations.
Sign-in/Register to access full text options 
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.
