What is a solar prominance?

Solar Prominences

High energy occurrences on or near the surface of the sun that are associated with its changing magnetic field. Typically, they are explosions caused by the very rapid release of energy stored in the magnetic field (although the exact mechanism is not known). These prominences usually appear as loops moving along, but not across, magnetic field lines that are anchored at both ends to the sun. Solar flares and sunspots are good examples of solar prominences.

Simple Answer: huge reddish loops of gas that often link different parts of sunspot regions.