Coronal Mass Ejections - A Statistical View

Although first recognized in 1971, the quasi-continuous record since 1979 of the appearance of coronal mass ejections (CMEs-perhaps more appropriately called coronal magnetic ejections) has resulted in a stable understanding of their properties, at least from a statistical viewpoint. These eruptions occur every few days during solar activity minimum and many times per day during maximum. They are believed to play an important role throughout the heliosphere in such diverse events as removing helicity from the corona; modulating the energetic particle environment in the inner heliosphere; causing severe geomagnetic storms at Earth and other magnetic bodies throughout the solar system; and controlling the galactic cosmic ray flux. It is therefore understandable that researchers have studied both individual events and the ensemble of CMEs observed over several solar cycles. We will present an overview of these statistics, some new recent observations, and a personal perspective on potential paths of future research.