Transient coronal holes are associated with coronal mass ejections and sunspost appear as dimmings in soft X-ray and extreme ultraviolet. They were proposed to be the footpoints of expanding magnetic flux ropes. This hypothesis has now been validated.
CME Initiation, Evolution, and Interplanetary ConsequencesGeorge Mason University scientists discovered recently that a phenomenon called a giant magnetic rope is the cause of solar storms. Though the magnetic rope was believed to be the cause of these giant eruptions on the Sun, scientists had previously not been able to prove this phenomenon existed because of how quickly the rope moves.
"The magnetic rope triggers a solar eruption. Scientists have been debating whether or not this magnetic rope exists before a solar eruption. I believe that the result of this excellent observation helps finally solve this controversial issue," says Zhang.
Scientists suspected that the magnetic rope, if it indeed existed, was the phenomenon that powered the eruption. A magnetic rope contains many magnetic field lines wrapping around a center axis and possibly twisting around each other. Because of the twisting, a strong electric current can be carried by the magnetic rope. Theoretically, the electric current could produce a sufficient electro-magnetic force to overcome the overlying constraining force from other field lines and power the magnetic rope to move outward.
AIA images now reveal that, before an eruption, there is a long and low-lying channel running through the entire active region, which heats to a temperature as high as 10 million degrees, and slowly rises. When it reaches a critical point, it starts to erupt quickly. It is a feature distinctly different from the surrounding magnetic field lines. This particular hot channel is now believed to be the magnetic rope that scientists have been looking for.
Scientists Prove Existence of 'Magnetic Ropes' That Cause Solar Storms