The animation above shows a
flare that occured on November 10th, 2012
from Active Region 11680. Click the animation for a longer movie, which
shows some additional activity from the previous day. This region exhibited the "S" shape that characterizes
what are known as
Sigmoids are of particular interest to
solar scientists because they are often associated with large flares
and coronal mass ejections (CMEs).
that sigmoids form from two opposing
J-shaped bundles of magnetic field lines. These pull together to form the "S" shape,
ultimately triggering flares and CMEs through
magnetic reconnection between the
joining field systems.