Coronal mass ejections: Solar cycle aspects

Research in the area of coronal mass ejections (CMEs) is now mature, since their discovery coincided with the first coronagraph that was flown in space in 1971. However, the continuity of space coronagraphs and similar instruments has allowed the detection and measurement of CMEs over almost three consecutive solar cycles. Their importance in the space weather field is well established, and some researchers believe the phenomenon may also be important for the longer-term space climate studies. In this review, we summarize the solar cycle variation of the main properties of CMEs detected by previous and ongoing missions. These include rate of detection, apparent angular width, detected mass, apparent speed, and apparent latitude. Their behavior in time is presented and discussed.