Polar Cap Magnetic Variations and Their Relationship with the Interplanetary Magnetic Sector Structure

摘要

The relationship between polar geomagnetic variations and the polarity of the interplanetary magnetic sectors has been studied for the quiet year 1965. It is found that during the day hours a system of ionospheric currents encircles the magnetic poles on every day. The current system may extend up to 15 degrees from the pole but is strongest at 8 - 10 degrees invariant colatitude. The current direction as seen from near the magnetic poles is counterclockwise during interplanetary sectors with field pointing away from the sun and clockwise during toward sectors. The current strength is dependent on season, being strongest during local summer. (Modified author abstract)