  Understanding the magnetic configuration of the source regions of coronal
mass ejections (CMEs) is vital in order to determine the trigger and driver of
these events. Observations of four CME productive active regions are presented
here, which indicate that the pre-eruption magnetic configuration is that of a
magnetic flux rope. The flux ropes are formed in the solar atmosphere by the
process known as flux cancellation and are stable for several hours before the
eruption. The observations also indicate that the magnetic structure that
erupts is not the entire flux rope as initially formed, raising the question of
whether the flux rope is able to undergo a partial eruption or whether it
undergoes a transition in specific flux rope configuration shortly before the
CME.
