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UBC Theses and Dissertations

Geomagnetic micropulsations with periods 0.3-3 seconds Jolley, Edmund Joseph


The classification and possible origin of geomagnetic micropulsations are discussed. In particular, pearls are described in some detail and previous investigations reviewed. Records from Victoria and Resolute Bay, Canada; Uppsala, Sweden; Reykjavik, Iceland; Huancayo, Peru; Ruth, Nevada and Isabella and Palomar, California are examined and the times of commencement and termination of pearl activity determined. The conclusion is reached that pearls in mid-latitudes are local mean time dependent and tend to occur during two periods of the day. These periods correspond roughly to sunrise and sunset, the times of rapid change in the critical frequency in the F₂ layer. Pearls seem to occur most often when the geomagnetic Kp index is less than 4o and greater than 0₊. No correlation is evident between occasional pearl-like signals at Huancayo and pearls observed at other stations. It is suggested that the appearance of pearls is to a certain extent controlled by local ionospheric conditions.

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