Space.com is carrying this article that details a recent discovery about the Earth's magnetosphere:

Pockets of superheated gas several times the size of Earth have been discovered swirling like bathtub drains high above the planet.

Turns out they're the result of interaction between the comparatively static "boudary layer" of Earth's magnetosphere and the extremely energetic solar wind. Sounds sort of like what happens when you run your hand knife-edge through a tub full of still water. Only bigger, and with plasma.