Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1778145 | Journal of Atmospheric and Solar-Terrestrial Physics | 2008 | 9 Pages |
Abstract
We present results of a statistical investigation of 99 magnetic clouds (MCs) observed during 1995-2005. The MC-associated coronal mass ejections (CMEs) are faster and wider on the average and originate within ±30â from the solar disk center. The solar sources of MCs also followed the butterfly diagram. The correlation between the magnetic field strength and speed of MCs was found to be valid over a much wider range of speeds. The number of south-north (SN) MCs was dominant and decreased with solar cycle, while the number of north-south (NS) MCs increased confirming the odd-cycle behavior. Two-thirds of MCs were geoeffective; the Dst index was highly correlated with speed and magnetic field in MCs as well as their product. Many (55%) fully northward (FN) MCs were geoeffective solely due to their sheaths. The non-geoeffective MCs were slower (average speed â¼382km/s), had a weaker southward magnetic field (average â¼-5.2nT), and occurred mostly during the rise phase of the solar activity cycle.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
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Authors
N. Gopalswamy, S. Akiyama, S. Yashiro, G. Michalek, R.P. Lepping,