Memoirs of the Kakioka Magnetic Observatory Vol.06 No.01， p.18, April, 1951
One of the Universal Variations of Geomagnetic Field(1st report)
Imamiti, S.
Abstract
There are some what stiff and peak from variations (these are called provisionally peak variation, and written p.v cursively) in geomagnetic field. This p.v is not special variation but it occurs ordinarily and it's amplitude is larger at the time of magnetic storm while it is smaller in calm day and single variation generally does not continue more than 20 minutes. The vectors of p.v all over the world except higher latitude are almost parallel each other, and their magnitudes become larger as the stations approach nearer to auroral zones.
It is most reasonable to consider that this p.v is due to Birkerland's ring current at auroral zone, and the author estimates as it's height at 2000 km, assumed it's position being 70°of latitude.
