Illustration of Ionospheric currents.
One contribution to the magnetic field of the Earth often varying rapidly in time, comes from outside the Earth, from current systems in the magnetosphere and ionosphere, driven by variations in solar activity or thermospheric winds.
During quiet periods the amplitude of these external contributions are about 20 nT at mid-latitudes, increasing to more than ten-fold over the magnetic storm times. A detailed knowledge of the near-Earth magnetic environment is crucial in so-called "space weather" studies.
Objectives of interest:
- Polar Ionosphere
- Mid- and Low-latitude Ionosphere