>>attention turns to a long dark filament of magnetism
Huh?
from: http://www.ips.gov.au/Educational/2/4/1
The bottom line is that at this stage in solar physics we do not really know what produces a flare nor what produces a CME. There are competing theories, but all tend to have deficiencies with respect to matching the observational evidence. We certainly believe that they all depend on the reconfiguration of magnetic fields as their primary energy source, but in the final analysis, we really only believe this because we can conceive of no other solar energy source of sufficient magnitude.