Study of geomagnetic storms, solar flares, and centers of activity in 1976, the year between solar activity cycles 20 and 21
Solar and geophysical circumstances prior to the 34 principal geomagnetic storms in 1976 have been evaluated. In this year of sun spot minima, 21 of the storms were unambiguously classified as sequential. For 7 of the storms prior flares may have played a role. Six of the storms remain as 'problem' situations. The 3 most severe storms in 1976 were associated with the 3 flares in 1976 with Comprehensive Flare Indices > or = 10. Inspection of plots of daily geomagnetic character figures suggest that at least 6 different sequences contributed to the geomagnetic disturbance in 1976. Relationships were sought between inferred coronal holes and the observed locations of significant centers of activity as the possible origins of the sequential storm particles. All of the major recurrent storm sequences in 1976 apparently had at their roots significant centers of activity that could have been near the perimeters of deduced associated coronal holes. The sequential storms occurred as the active regions were dying and continued long after all optical events of the active regions had disappeared.
- Research Organization:
- Johns Hopkins Univ., Silver Spring, MD (USA). Applied Physics Lab.
- OSTI ID:
- 5866762
- Report Number(s):
- AD-A-098936/8
- Country of Publication:
- United States
- Language:
- English
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