“The Steve arc appeared for only about 20 minutes, starting at 10:45 pm MDT, during a lull in the main display,” says Dyer, who captured the arc in a 6-shot, 360^o panorama.

For many years, northern sky watchers have reported this luminous form occasionally dancing among regular auroras. It was widely called a “proton arc” until researchers pointed out that protons probably had nothing to do with it. So members of the Alberta Aurora Chasers group gave it a new name: “Steve.”

“We seem to be ideally located in the Canadian Prairies for sighting Steve, as we often get the main aurora to our north, placing Steve overhead or to our south,” notes Dyer.

No one fully understands the underlying physics of the purple ribbon. One of the European Space Agency’s Swarm satellites flew straight through Steve during a previous apparition. Data revealed a relatively hot river of gas, about 25 km wide, flowing rapidly through Earth’s outer atmosphere. “Steve seems to be a thermal emission from hot flowing gas rather than from precipitating electrons,” says Dyer, “but his origin and nature are still mysterious.”

Source: Spaceweather.com