Electrical tornadoes in space as drivers of the Northern Lights

Andreas Keiling
Space Sciences Lab


Tornadoes on Earth are among the most violent storms, capable of enormous destruction with wind speeds of 200 mph and more. Yet these are tiny compared to the "space tornados" that impress with flow speeds of more than one million mph and beautiful auroras. Both terrestrial and space tornados are similar in that they consist of funnel-shaped structures. However, the space tornadoes are composed of rotating clouds of charged particles, called plasma, with embedded twisted magnetic field lines. In addition to the fast flows, space tornados generate huge amounts of electric currents, more than one hundred thousand Amps, inside the funnel. These currents are channeled into the ionosphere where they power several processes, most notably bright auroras. While these intense currents do not cause any direct harm to humans, they can damage man-made structures, such as power transformers, on the ground. Located about forty thousand miles away from Earth, the space tornadoes span a volume of the size of the Earth and larger. The results of this study were obtained from the current NASA space mission called THEMIS, named after the Greek goddess of blind justice and stands for Time History of Events and Macroscale Interactions during Substorms. Launched in February 2007, THEMIS is comprised of five spacecraft and an extended network of ground observatories spread out over North America. THEMIS is operated by SSL-Berkeley. In this talk, I will describe the THEMIS mission, the observations of the space tornadoes and their effects on the ionosphere and on life on Earth.