External Magnetic Fields

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  
  • CHAMP: Quiet Polar Passes
  • High-latitude Plasma Convection
  • Small Scale Field Aligned Currents

• Mid- and Low-latitude Ionosphere  
  • Equatorial Electrojet
  • Equatorial Plasma Instabilities
  • Solar Eclipse Effects in the Upper Atmosphere

• Thermosphere  
  • Polar Thermospheric Density
  • Equatorial Thermospheric Winds

• Substorms  
  • Magnetic signatures and improved current system
  • Thermospheric response