External Field

One contribution to the magnetic field of the Earth often varying rapidly in time and space has its sources in near Earth space. These magnetic signatures are from electric current systems in the magnetosphere and ionosphere, driven by solar radiation or thermospheric winds.

Impact of solar particel radiation on the Earth's magnetosphere. (Artists view; not to scale)

During quiet periods the amplitude of these external contributions are about 20 nT at mid-latitudes, increasing to more than ten-fold during geomagnetic storms. A detailed knowledge of the near-Earth magnetic environment is crucial in so-called "space weather" studies. The IAGA-endorsed Kp-index characterizing global geomagnetic activity is provided by the Niemegk geomagnetic observatory.


Profile photo of  Prof. Dr. Claudia Stolle

Prof. Dr. Claudia Stolle

Behlertstraße 3a
Building K 3, room 006
14467 Potsdam
tel. +49 331 288-1230