|Power transformer in New Jersey, US, burnt|
out due to induced current caused by a
geomagnetic storm in March 1980.
THEMIS view of the Magnetotail
|The THEMIS spacecraft in the clean room |
mounted on their launch platform.
All the processes in the Earth's magnetotail that lead to the reconfiguration of the magnetic field, through stretching, reconnection, fast flows and generation of the aurora are called a magnetospheric substorm. The word substorm is a bit antiquated, because in the beginning people thought that a geomagnetic storm (another energetic phenomenon of the Earth's magnetosphere, which lasts much longer) was build up from a set of smaller substorms. Although this idea was proven wrong, the name substorm stuck.
|The "outside-in" model for substorms|
|The "inside-out" model for substorms|
Unfortunately THEMIS is no longer. The spacecraft are still in space and working, but the mission has changed. The two outermost spacecraft have had their orbits majorly changed and were send to the Moon in 2011, where they now operate under the name ARTEMIS. The three innermost spacecraft remained in their near-Earth orbits.
Magnetospheric Multi Scale (MMS) mission, which is going to be another 4 spacecraft mission, similar to Cluster in a tetrahedron configuration, but now the spacecraft will be much closer together, 30 - 400 km. MMS will look at the dynamic processes in the tail at the "electron scale." Basically, this mission will "zoom in" on e.g. the reconnection process that was measured by the Cluster mission and get a more detailed view on smaller scales of what is going on. The planned launch is in October 2014.