Coronal mass ejection

We summarize the observational aspects of the transient solar coronal features known as coronal mass ejections. Recognizing the importance of understanding this form of solar activity, particularly in the light of relations to flare and prominence activity, and geomagnetic effects, we consider the spectrum of models which have been used to describe these events and assess their viability. We find most models to be unphysical and all represent a gross over simplification of solar conditions. In conclusion we set up a cartoon model which best fits the observations and which we feel should be further developed.