Streamer belt seen in the field of view of the LASCO C2 coronagraph.
The upper panel shows the current sheet during a quiet period; the
lower panel shows the same area two days prior to the February 3 CME.
The obvious increase in brightness prior to the CME indicates that more
material is stored before a global coronal disturbance than during
quiet coronal periods.  It is assumed that the current sheet will blow
open when the pressure inside exceeds a certain value.   An instability
will then accelerate and release the stored hot coronal material as a
global coronal disturbance.  Upper panel:  during a quiet period.
Lower panel:  during an active period prior to a coronal mass ejection.
The field of view covers 1.6 to 6 solar radii.