Although our final prediction was designed to predict the steady or slowly evolving structure of the solar corona, there is no guarantee that the Sun will cooperate during the eclipse!
Just a week before, on August 14, the STEREO-A spacecraft observed a nice solar eruption. This event, also known as a Coronal Mass Ejection or CME, originated from an active region rotating into view. This same region will be visible on the east limb (the left side of the Sun) on eclipse day.
The movies above show an animation of one of our model runs leading up to the final prediction. In a lucky coincidence, we over-energized the magnetic field in the same region, and produced a nice CME in our model.
Each frame in the animations is approximately 10 minutes. The path of totality will take about 90 minutes to sweep across the continental United States. This means that if a CME happens around eclipse time, we might catch an important part of its evolution!