24th Cycle of Solar Activity: Geoefficiency of Flares

Abstract

Various aspects of the of geoefficiency of solar-activity phenomena, such as flares and coronal mass ejections (CMEs), are considered. The number of geoefficient events was about two times lower in the 24th cycle than in the 23rd cycle. Statistical data on major flares and the Dst index in different phases of the 24th cycle is compared. Large flares (X-ray class > M5) were analyzed based on data from GOES-15 satellite observations in the 24th solar activity cycle. The three main geomagnetic indices, Ap, Kp, and Dst, were analyzed in comparison with the F10.7 index and the sunspot number (SSN).