Open AccessDependence on Geomagnetic Activity of Magnetic Pulsation Frequency of pc‐3 and pc‐4 Ranges
Author(s) -
Nagata T.,
Fukunishi H.
Publication year - 1968
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1968.tb05746.x
Subject(s) - plasmasphere , earth's magnetic field , physics , solar wind , ionosphere , low frequency , computational physics , magnetic field , very low frequency , geophysics , atmospheric sciences , astrophysics , magnetosphere , astronomy , quantum mechanics
Summary Frequency spectra of magnetic pulsations of frequency range from 5 to 100 mHz observed at temperate latitudes consist of two dominant frequency bands, 15 mHz and 35 mHz in their representative average values. The frequency of both bands increases with an increase of geomagnetic activity represented by K p or K p . The time of occurrence of maximum frequency in both bands in their regular daily variation of frequency advances towards the dawn side with an increase of K p It seems likely that the resonators for the 15 mHz and 35 mHz bands can be identified respectively to a standing Alfvén wave along the field line on the plasmapause and a standing modified Alfvén wave between the plasmapause and the ionosphere. Then, the increase in frequency and the dawnward shift of maximum frequency time can be ascribed to a contraction and a deformation, respectively, of the plasmapause caused by an intensified solar wind accompanied by an increase in K p ‐index.