Relation between interplanetary sector structure and geomagnetic activity near the minimum of sunspot cycle
Abstract
Effects of interplanetary sector structure on geomagnetic storms near the minimum of the sunspot cycle are investigated. The summed K index at Kakioka increased significantly for a day after passage of the sector boundary and decreased very rapidly from the second day following the peak value during 1964-1967, but during the period of July 1972 to June 1975, the summed K index increased for three days after sector boundary passage and then decreased rapidly after reaching the maximum in the away sector. In the toward sector, activity continued until seven days after sector boundary passage. The 27-day recurrence of geomagnetic storms holds for both gradually and suddenly commencing storms during the period of sunspot minimum. It is suggested that most of the geomagnetic disturbances can be explained by the interaction between corotating distortions in the solar wind connected with the sector structure and the magnetosphere.
- Publication:
-
Kakioka Magnetic Observatory Memoirs
- Pub Date:
- March 1978
- Bibcode:
- 1978MmKMO..17...87N
- Keywords:
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- Interplanetary Magnetic Fields;
- Magnetic Storms;
- Solar Activity Effects;
- Sudden Storm Commencements;
- Sunspot Cycle;
- Twenty-Seven Day Variation;
- Diurnal Variations;
- Earth Magnetosphere;
- Solar Corona;
- Solar Wind;
- Solar Physics