New knowledge about Earth’s magical magnetic field

Friday 11 Oct 13


Chris Finlay
DTU Space
+45 45 25 97 13

A DTU researcher and his French colleagues are one step closer to explaining what is going on deep inside the Earth. In a recently published article in Nature, they explain how the Earth’s magnetic field is formed and describe how it impacts the surface.

Interaction thousands of kilometres down
“This is the first time that someone has developed a precise model for how the inner and outer core interact to generate the Earth’s magnetic field. In addition, the model accounts for the variations generated by the magnetic field. How do they arise—and can they be predicted? They are processes taking place 2900 kilometres beneath our feet, but which are nevertheless very important for all of us here on the Earth’s surface. And that the inner core plays such a significant role, as demonstrated by our new model, is a surprise indeed,” explains Chris Finlay, Senior Scientist, DTU Space.

The Earth’s magnetic field is the shield protecting us against harmful particles from space—also known as solar storms. However, how this shield is changing and developing has, until now, been difficult to predict, even just a couple of years ahead. But by linking processes in the two parts of the core—the liquid outer and the solid inner—researchers have been able to create an explanatory model which offers new and more in-depth understanding of the processes.

New discoveries using Danish data
The new model has facilitated several interesting discoveries. Data from the Danish Ørsted satellite, which have been analyzed by the research group, indicate that changes in the magnetic field happen primarily in the Atlantic. And the basis for changes seems quite fascinating as everything in the new model suggests that the inner core is growing asymmetrically.

We thus have been given a deeper understanding of why the Earth's magnetic field moves 0.2 latitudes to the west every year—something which has previously been a bit of a mystery.

Swarm satellites to provide more knowledge
The Swarm satellites—launched on 14 November this year—will strengthen further work with the model. Swarm was originally a Danish proposal which the European Space Agency (ESA) has adopted, and since realized in cooperation with DTU Space.

“The highly accurate data from Swarm will enable us to further improve our studies of the interaction between the inner and the outer core and thereby provide us with more knowledge about the Earth's magnetic field, ultimately offering us a fundamental understanding of the amazing processes deep inside our planet.”