Research at the GFZ makes an important contribution to the understanding of sun-driven processes. Models of the Earth's magnetic field, the ionosphere and thermosphere as well as the real-time and forecast models for space weather must be further developed in a highly complex and dynamic research environment. The continuously calculated (real-time) forecasts are also crucial for the operators of critical infrastructures and space-based systems.

The research work on space weather is primarily carried out in the GFZ sections 2.3 "Geomagnetism" (development and provision of data products) and 2.7 "Space Physics and Space Weather" (forecasts and modelling). The most important current research projects in this subject area are presented below.

The geomagnetic Hpo index is a Kp-like index with a time resolution of half an hour, Hp30, or one hour, Hp60. The Hpo index is also open-ended and describes the strongest geomagnetic storms in a more nuanced way than the three-hour Kp index, which has a maximum value of 9. The Hpo index was developed in the H2020 project SWAMI and is described in Yamazaki et al. (2022, doi.org/10.1029/ 2022GL098860).

Detailed information on the Kp index and data access
Product for the European Space Agency ESA | Geomagnetic services
Space Weather | GFZ space weather forecast

The Earth's magnetic field protects us from the incessant stream of charged particles, the solar wind, even before it reaches the upper atmosphere. However, the main axial component of the Earth's dipole-like magnetic field (and thus the protection from energy-rich particles) is decreasing at a rate ten times higher than if the field were simply decaying. This decrease amounts to around 8 percent over the last 150 years. In some areas, such as the South Atlantic Anomaly, it has even been 8 percent in the last 20 years alone. As a result, for example, satellite failures are observed more frequently over this region than elsewhere and passengers on long-haul flights are exposed to increased radiation doses. The scientists cannot say how long the current South Atlantic anomaly will last. The field strength could continue to decrease for several centuries. In order to understand how this weakening shield will develop in the future, it is essential to accurately map the changes in the geomagnetic field over time.

More on the South Atlantic Anomaly

The main magnetic field from the earth's core, which changes only very slowly, is also of practical importance as a backup if navigation satellites are affected by geomagnetic storms or even fail completely. The strength alone is not enough to fully describe the Earth's magnetic field. The directions in space must also be specified. This is possible, for example, using two angles called (compass) declination and inclination. The GFZ declination calculator can be used to determine not only the compass declination, but also the strength and inclination angle of the magnetic field for every point on Earth and for all times between 1900 and 2025.

The calculation is based on the International Geomagnetic Reference Field, which describes the Earth's main magnetic field generated in the Earth's core. As a rule, a calculation accurate to the year (not to the day) produces values that are sufficiently accurate for navigation with the magnetic compass. In the event of a potential failure of global navigation systems, the magnetic compass is of great importance. In some places on earth, strong local magnetic field anomalies exist due to magnetised rocks in the earth's crust. These anomalies can lead to deviations in the compass deflections from the calculated values.

The main objective of the Swarm mission is to provide the best overall picture of the geomagnetic field and its development over time. Each of the three identical satellites collects high-precision and high-resolution measurements of the strength and direction of the magnetic field. In combination, they provide the necessary observation data required for modelling the various sources of the Earth's magnetic field. In addition to data on the Earth's magnetic field, the mission also provides data on ionospheric and atmospheric parameters. The Swarm satellite mission launched by the European Space Agency (ESA) in 2013 was not specifically designed as a magnetic field mission for space weather observation. However, numerous data products from this mission are useful for characterising space weather conditions. The ESA and the international scientific consortium in which the GFZ is involved are therefore working on the development and implementation of data processing algorithms in near real time. Swarm continues the important observation of the Earth's magnetic field from space, which was largely carried out from 2000 to 2010 by CHAMP, a satellite of the GFZ and the German Aerospace Centre DLR.

ESA has been producing and providing Swarm Level 1b FAST data products since November 2023. The GFZ is currently working on adapting Level 2 data products for the European Space Weather Service Network in order to expand the range of products it already regularly supplies to the European Space Agency.

GFZ Satellite data products
GFZ space weather products
10 years Swarm mission (article from 22/11/2023)
Further information on the Swarm Mission of the European Space Agency ESA

The Earth's magnetic field and its magnetosphere show significant fluctuations on time scales ranging from hours (geomagnetic storms) to millions of years (field reversals). Magnetic measurement data include:

•  Proportions of the main field generated by geodynamo processes in the Earth's outer core
• Proportions of the lithospheric field of magnetised rocks and geological structures
• Components of highly variable magnetic fields from electric systems in the ionosphere and magnetosphere
• Secondary components from induction in conductive structures in the Earth's crust and mantle

In order to understand the individual sources and their significance for the development of the main field, space weather conditions and the interpretation of crustal anomalies, a clear separation of the components is necessary. This is still a challenge and requires further research.

GFZ models of the geomagnetic field

Space weather monitoring and forecasting is currently carried out by a number of space weather centres around the world. Reliable forecasts during active geomagnetic conditions can help satellite operators to put satellites into a protection mode, avoid maintenance, issue warnings and to better understand the reasons for anomalies. The GFZ provides important forecasts for space weather in real time, such as for the ring current, the plasmasphere and the radiation belts. We also develop models of the entire space environment (heliosphere, magnetosphere and ionosphere).

In the European Research Council project "Waves in the Inner Magnetosphere and their Effects on Radiation Belt Electrons | WIRE", led by Dr Dedong Wang, waves and high-energy electrons in the space environment are being quantified. The aim is to use this data to better understand the dynamics of high-energy particles and to predict harmful radiation in space more accurately. The project also addresses the question as to why the Earth's radiation belts react differently to geomagnetic storms of roughly the same intensity.

Further information on the research prize and the WIRE project

At ultra-relativistic energies, electrons move at almost the speed of light. The laws of relativity then come into play. The mass of the particles increases by a factor of ten, time passes more slowly for them and distances become shorter. With such high energies, the charged particles become a danger to satellites: Because they cannot be shielded, they can destroy the sensitive electronics of satellites due to their charge. Predicting their occurrence is therefore very important for modern infrastructure.

Scientists at the GFZ are investigating the conditions for the enormous acceleration of electrons with the help of detailed measurements in the radiation belt. The radiation belt surrounds the Earth in a donut shape in near-Earth space. A mixture of positively and negatively charged particles forms what is known as plasma in the radiation belt. Waves of this plasma are created by fluctuations in the electric and magnetic field and are stimulated by solar storms. These plasma waves in turn are an important driving force for the acceleration of electrons, i.e. the ultra-relativistic energies.

The scientists were able to observe both solar storms that cause ultra-relativistic energies and solar storms that do not. They found that ultra-relativistic energies occur more frequently when the plasma density is only around ten particles per cubic centimetre. The plasma density, in turn, can be calculated from measured fluctuations in the electric and magnetic field.

To the GFZ article: "How do electrons close to Earth reach almost the speed of light?"

The terrestrial ring current is an electric current that surrounds the earth at distances between ~3 and ~5 earth radii from the centre of the earth in the equatorial plane. During geomagnetic storms, the ring current intensifies and reduces the Earth's magnetic field. During the recovery phase of the storm, the ring current decays due to scattering of charged particles by field changes, plasma waves (e.g. electromagnetic ion cyclotron waves) or charge exchange with neutral atoms. The ring current is a crucial component for our understanding of magnetospheric dynamics and geomagnetic storms. At high latitudes, it can affect critical infrastructure such as power grids or communication and navigation satellites.

Information on research and modelling of the terrestrial ring current at GFZ