Coronal Holes and the Solar Wind
The coronal holes are regions where
the magnetic field lines of the Sun are open, allowing coronal gas to flow
outward into space to produce the solar wind. In contrast, the capped-looking
streamers in the corona (helmet streamers) seen in the images on the first page of the
left panel correspond to
regions in which the magnetic field lines are closed in a loop.
This traps the coronal gas
and leads to enhanced X-ray emission because of the increased gas densities.