The magnetic field radiates around the Earth and far into space, but it is set by processes that happen deep within its core, where temperatures exceed 5,000 degrees Celsius.
A new study from researchers at the University of Leeds suggests that the way this super-hot core is cooled is key to understanding the causes of anomalies of the Earth’s magnetic field.
In the extremely hot temperatures found deep within the Earth, the core is a mass of swirling, molten iron which acts as a dynamo. As the molten iron moves, it generates the Earth’s magnetic field.
Seismic studies have identified that there are regions of the mantle, under Africa and the Pacific for instance, that are especially hot. Computer simulations have revealed that these hot zones reduce the cooling effect of the core which causes regional ro localized changes to the properties of the magnetic field.
For example, where the mantle is hotter, the magnetic field at the top of the core is more likely to be weaker.
Dr. Mound, who led the study, said, “One of the things that the magnetic field in space does is deflect charged particles emitted from the sun. When the magnetic field is weaker, this protective shield is not so effective.
“So, when satellites pass over that area, these charged particles can disrupt and interfere with their operations.”
Dr. Mound added, “Processes in the mantle happen very slowly, so we can expect the temperature anomalies in the lower mantle will have stayed the same for tens of millions of years. Therefore, we would expect the properties of the magnetic field they create also to have been similar over tens of millions of years.
“But the hotter, outer core is quite a dynamic fluid region. So, the heat flows and the magnetic field properties they cause will probably fluctuate on shorter time scales, perhaps for 100’s to 1000’s of years.”
https://phys.org/news/2023-03-hot-topic-affects-earth-magnetic.html