Substorm

A magnetospheric substorm (English [ magnetospheric ] substorm ) is a short disruption in the magnetosphere of a planet that causes the release and diversion of energy from the " tail " of the magnetosphere in the near-polar ionosphere. Visually makes its appearance there as sudden illumination and increased movement of auroral arcs. Substorms first described the Norwegian scientist Kristian Birkeland as "polar elementary storms ". Sydney Chapman took around 1960 the term " substorm ", which is now the standard term. The morphology of a substorm first described the Japanese geophysicist Syun -Ichi Akasofu in 1964 on the basis of data from the International Geophysical Year.

Substorms differ from magnetic storms by the latter extend for days, can be seen everywhere on the planet, a large number of ions in the outer Van Allen radiation belts initiate and during the peak period of the solar wind activity once or twice per month, while low times few occur times per year. However, substorms occur over a period of a few hours, are mainly observed in the polar region, bring a few particles in the radiation belts and are relatively often by are only a few hours apart often. Substorms are piling up during a geomagnetic storm, where they often overlap with the following. The source of the observable on the surface of magnetic interference during magnetic storms, the ring current in part storms are electric currents in the near-pole ionosphere.

Substorms, magnetic field disturbances in the Polarlichzonen up to field strengths of about 1000 nano Tesla, about 2 % of the total field strength in these regions. The disorder is much stronger in space, where some geosynchronous satellites have observed dips to half of the field strength. The most visible signs of a storm part are enhanced and more extensive auroras. Substorms occur about six times daily, where they are more common during a geomagnetic storm and be stronger. It describes three phases: construction, expansion and recovery.

The THEMIS mission observed in 2012 the dynamics of a rapidly developing part of the storm and confirmed the existence of giant magnetic tapes and witnessed small explosions in the outer regions of the Earth's magnetic field.

Swell

• Planetology
• Magnetics