Anatomy of a Cme

Angelos Vourlidas, SECCHI Project Scientist: My name is Angelos Vourlidas, and I'm the Project Scientist for the SECCHI instrument suite on STEREO. A coronal mass ejection is...it's an explosion of the sun's atmosphere that propagates in space in the form of a cloud. They can really disrupt satellite communications, they can affect GPS signals, our cell phones, and even cause electricity disruptions. So the STEREO satellites...is a mission specifically to study the coronal mass ejections using two identical spacecraft so we can reconstruct the three-dimensional structure of these clouds. The use of a single spacecraft, it's similar to seeing the world with one eye. You suddenly lack perception of depth, and we never know if the object, for example, is coming towards us, going away from us. By injecting the second viewpoint, then suddenly you run out of solutions, and you have a very limited number of models to choose from. So this...the shape of a CME seems to be similar to a French croissant, only instead of being comprised of pastry, it's comprised of magnetic field lines. We basically have moved halfway towards solving the problem at least in a practical manner. By modeling and getting ground truth on the shape and the energy on the CME, we can make better predictions of when they will erupt and how violent the eruption will be.