Abstract The cyclical behaviors of sunspots, flares and coronal mass ejections (CMEs) for 54 months from 2008 November to 2013 April after the onset of Solar Cycle (SC) 24 are compared, for the first time, with those of SC 23 from 1996 November to 2001 April. The results are summarized below. (i) During the maximum phase, the number of sunspots in SC 24 is significantly smaller than that for SC 23 and the number of flares in SC 24 is comparable to that of SC 23. (ii) The number of CMEs in SC 24 is larger than that in SC 23 and the speed of CMEs in SC 24 is smaller than that of SC 23 during the maximum phase. We individually survey all the CMEs (1647 CMEs) from 2010 June to 2011 June. A total of 161 CMEs associated with solar surface activity events can be identified. About 45% of CMEs are associated with quiescent prominence eruptions, 27% of CMEs only with solar flares, 19% of CMEs with both active-region prominence eruptions and solar flares, and 9% of CMEs only with active-region prominence eruptions. Comparing the association of the CMEs and their source regions in SC 24 with that in SC 23, we notice that the characteristics of source regions for CMEs during SC 24 may be different from those of SC 23.
Keywords Sun: coronal mass ejections (CMEs) — Sun: filaments, prominences — Sun: flares — sunspots
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