Pc 3 magnetic pulsations observed at low latitudes: A possible model

• Main Authors: Yumoto,Kiyohumi, Saito,Takao, Tanaka,Yoshihito
• Format: Report
• Language: English
• Published: Onagawa Magnetic Observatory and Geophysical Institute, Tohoku University/Onagawa Magnetic Observatory and Geophysical Institute, Tohoku University/Research Institute of Atmospherics, Nagoya University 1987
• Subjects: Pedersen; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2160; http://id.nii.ac.jp/1291/00002160/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2160&item_no=1&attribute_id=18&file_no=1

It is recently demonstrated that Pc 3 magnetic polarizations observed at equatorial latitudes (|φ|<20°) are different from those at low-latitude Japan-Australia conjugate stations (|φ|∿35°). In order to interpret the Pc 3 polarization characteristics at lower latitudes (|φ|≲45°), we propose a probable, new qualitative model in which two (or more) superimposed ionospheric eddy currents, oscillating with slight differences in frequency in the Pc 3 range and in apparent azimuthal wave number, move azimuthally at low latitudes (|φ|≲45°). Near low latitudes of |φ|∿45°ionospheric rotational Hall currents should be induced by field-aligned currents associated with localized shear Alfven waves which are excited by compressional Pc 3 source waves near |φ|∿45°. Near the equatorial region ionospheric Pedersen eddy currents may be caused by inductive electric fields of compressional Pc 3 source waves which would propagate from the outer magnetosphere to the equatorial ionosphere.