Open AccessAmplitudes and Periods of Geomagnetic Micropulsations in the Pc3, 4 Range at Canadian Observatories
Author(s) -
Stening Robert J.,
Gupta Jagdish C.
Publication year - 1971
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1971.tb01830.x
Subject(s) - amplitude , latitude , geomagnetic latitude , earth's magnetic field , diurnal temperature variation , local time , variation (astronomy) , atmospheric sciences , range (aeronautics) , low latitude , geodesy , climatology , geology , physics , astrophysics , mathematics , magnetic field , materials science , optics , quantum mechanics , composite material , statistics
Summary Amplitudes and periods of Pc3, 4 micropulsations have been measured during selected intervals between July 12 and August 16, 1968. Simultaneous records at the four observing sites showed considerable differences in the variation of amplitude and period with latitude on different occasions but the amplitudes were usually maximum in the auroral zone. A study of the amplitudes at different local times revealed a poleward shift of the latitude of maximum amplitude from night to day. At times of lower Cp the afternoon Pc maximum reverted to a lower latitude. The change from day to night is ascribed to the shape of the auroral oval and the competing effects of ‘diffuse’ and ‘discrete’ processes. Correlation of Pc amplitudes with Kp showed considerable diurnal variation and at some local times (20‐22 hLT at all stations) was not significant. No consistent variation with latitude of mean Pc3, 4 periods was found. Pc3 periods were smaller at times of higher Kp while Pc4 periods were larger.