Photo: Heikki Ketola
The Finnish Meteorological Institute has taken part in the Themis Project that has provided new information on space tornadoes. It has been discovered that huge space tornadoes give rise to auroras on the Earth when the tornadoes hit the ionosphere. The tornadoes can also interfere with electronic equipment on the Earth and in space.
Tornadoes in the Earth's atmosphere belong to the most dramatic weather phenomena. Their funnel-shaped cyclones can be several km high, and the wind speed inside the funnel reaches several hundreds of km/h, causing severe damages when they touch down to the ground.
- Compared to a space tornado, the weather tornado still appears tiny, said FMI senior scientist and docent of Space Physics at the University of Helsinki, Olaf Amm, at a press conference at the recent European Geophysical Union Meeting in Vienna together with his colleagues Andreas Keiling (University of California, USA) and Karl-Heinz Glassmeier (Technical University of Braunschweig, Germany). In a space tornado, plasma rotates with velocities of more than one million km/h, and each of the two funnels of the tornado has a size larger than the Earth.
Tornados can cause damages to electronic equipment
The full structure of such a tornado has now been discovered for the first time with the US-led Themis-mission that consists of five spacecraft in the Earth's magnetosphere, an area of space that is governed by the influence of the Earth's magnetic field. Currents of more than 100.000 Amps were observed in the funnels of the space tornado, and the currents as well as strongly energized particles are directed towards the Earth by the funnels. In contrast to the weather tornado, the Space tornado touches down in the Earth's ionosphere, a conducting layer of the upper atmosphere in about 100 km altitude. The scientists were able to directly observe the touchdown of both funnels of the space tornado using a technique developed by Olaf Amm at FMI, which allows to compute the currents in the ionosphere from data of the extensive Themis network of ground magnetic observations. Two vortices of intense ionospheric currents created by the touchdown released an estimated power of more than 10 GW in the ionosphere, corresponding to several nuclear power plants.
- The tornado powered intense aurora which was observed by a network of cameras. For humans, space tornadoes do not cause any direct danger, however they can cause damages to electronic equipment both on the ground and in space. Scientists at FMI, together with their international collaborators, are therefore working on a better prediction of such phenomena, Olaf Amm says.
Olaf Amm, tel. +358 9 1929 4689, firstname.lastname@example.org