Some Observations of Geomagnetic Micropulsations

Abstract

New observations are reported of the diurnal variation, direction, frequency spectrum, and geographical distribution of geomagnetic ~nicropulsations (PC and Pt). I t is argued from a conlparison of published data that these phenomena have pri~narily a solar time dependence, and may occur locally. A t our two stations, separated by 60 longitude degrees, related signals are only occasionally observed. The phase characteristics of such related signals, together with differences in directional characteristics reported by other observatories, put serious strain on recent theories of the outer atnlospheric origin of micropulsations.

Morphology of the Geomagnetic Pulsation

“…The phase of the vertical component always lags to that of the N -S component (Terada, 1917). contrast to the result of Duffus and Shand (1958); they found little phase-difference between both components . speaking, the rotation-sense shows a semi-diurnal variation (Terada, 1917).…”

“…It may be rather labourious and mistakable to read with eyes as in the cases of Holmberg (1953) and Angenheister (1954). Duffus and Shand (1958) make use of a harmonic analyser for this purpose.…”

“…In that case, one may suppose that pulsations of shorter period (i) The mean amplitude of pulsation is greater, when the period is longer (Angenheister, 1954;Duffus and Shand, 1958). According to Duffus and Shand (1958), there are peaks around 1 and 2 minutes (Fig.…”