Section 2.3: Geomagnetism

Artificial illustration of Swarm satellite mission.
(EADS Astrium)
Interhemispherical field align currents and Sq current system.
(GFZ Potsdam)
Visualisation of a Martian crustal magnetization model.
(GFZ Potsdam)
Northern lights (aurora borealis) appeared during the geomagnetic storm of March 17, 2015 – the so far strongest storm of the present solar cycle.
(GFZ Potsdam)
Artistic view of the temporal variation of the fluid flow at the core-mantle boundary estimated from a magnetic field reconstruction of the past 7000 years.
Aerial view of the geomagnetic observatory in Niemegk.
(Richard Holmes)
Magnetic signal of the ocean tidal flow.
(GFZ Potsdam)
Old Schmidt theodolite in Niemegk observatory
(GFZ Potsdam)

The geomagnetic field is our natural shield against solar wind particles and cosmic radiation. It is mainly generated by dynamo processes in the Earth's outer fluid core. Magnetized rocks in the Earth's crust, electrical currents in ionosphere and magnetosphere and even ocean currents add contributions to the Earth’s magnetic field. We use geomagnetic field observations and data from other plasma or atmospheric parameters obtained from ground and space instrumentation to investigate the dynamic processes inside the Earth and in the near-Earth space environment. Our aim is to better understand space weather conditions and the future evolution of the geomagnetic field.

Working Groups

Geomagnetic field evolution

Geomagnetic field lines at the core mantle boundary (CMB)
(GFZ Potsdam)

The investigation of secular variation of the geomagnetic core field on all time scales is relevant to better understand the dynamics of Earth’s core and the geodynamo process. Our reconstructions of the global geomagnetic field on historical to paleomagnetic time scales in addition inform about long-term variations in shielding against solar wind and cosmic radiation.

Geomagnetic Variations

Interhemispherical field align currents and Sq current system.
(GFZ Potsdam)

The Earth's magnetic field is not static but constantly changing. The variations in the geomagnetic field on time scales of minutes to days are primarily of external origin; that is, the source electric currents flow in the ionosphere (a few hundreds of kilometers from the surface) and magnetosphere (several Earth radii from the surface). Studies of those geomagnetic perturbations are, therefore, important for understanding the physical processes in the Earth's upper atmosphere and near-Earth space, which is necessary for the predictions of space weather and climate.

Ionosphere and Upper Atmosphere

The ionosphere is the ionised part of the upper atmosphere, which builds up through absorption of solar electromagnetic and particle radiation. Electric currents in the ionosphere produce signatures in the Earth’s magnetic field, both during geomagnetically quiet and disturbed times. We investigate different topics that relate to the interaction between the upper atmosphere, the magnetic field, and the solar radiation.

Geomagnetic Observatories

Globally distributed geomagnetic observatories deliver high-quality, continuous measurements of the Earth’s magnetic field. They give knowledge on changes occurring in the Earth’s core as well as in near-Earth space and they facilitate the best possible interpretation of satellite-borne magnetic measurements. Real time data are an important tool for the monitoring of acute space weather incidents. GFZ’s global network of geomagnetic observatories and associated cooperation programmes are operated from the Niemegk observatory.

Monika Korte
Dr. Monika Korte
Albert-Einstein-Straße 42-46
Building A 42, Room 227
14473 Potsdam
+49 331 288-1268