Large‐scale structures and multiple neutral lines associated with coronal mass ejections

We use Yohkoh soft X‐ray telescope (SXT) images of eruptive events visible against the solar disk to examine the coronal structures and the boundaries of the large‐scale magnetic fields considered to be involved in coronal mass ejections (CMEs). From an initial list of about 100 large‐scale events we selected five for detailed study. The transient X‐ray structures in these events spanned distances across the solar surface ranging from 35 to >100 heliographic degrees, comparable to the spans of white light CMEs observed at the limb. The widths of the coronal loop arcades spanned two or three neutral lines, or a single, highly convoluted neutral line. Our interpretation of these results is that multipolar magnetic systems are a common configuration of the source fields of many CMEs, contrary to the first‐order approximation that CMEs involve the eruption of simple, bipolar structures.