What is the most convinscing theory that discusses the generation of Earths magnetic field?
Many Geophysical references referred to magmatic currents which are rich in iron content and located at the lower mantle and outer core composes the main source of magnetic field. Iwould like to know if there are any new theories or any other references that discuss this subject.
It is very difficult to know exactly how the Earth's magnetic field is formed, since we do not have access to the place where it is formed. What we know is that between a 90 and a 95% of the magnetic field is a dipole. It is widely accepted that the magnetic field is produced in the outer core (which is Fe and Ni in liquid state). There is no other place on Earth capable of generating a magnetic field. Recent computer simulations seem to support the so-called geodynamo hypothesis. In which the outer core would produce a toroidal flow that produces the Earth's magnetic field.
You can get a nice introduction to Earth magnetism with Tauxe's book. I have also provided a popular science paper about the geodynamo.
https://earthref.org/MagIC/books/Tauxe/Essentials/
http://www.scientificamerican.com/article/probing-the-geodynamo-2005-07/
Thank you Dr. Galan for your answer , and I enjoyed reading the refrernces.
It is known that outer core magmatic conviction currents works as a giant coils producing magnetic fields and the resultant of summing the fields of those giant coils represents the main Earth's magnetic field. But, there are still some questions that make the hypothesis ambiguous such as:
What is the source of the huge electrical current that moves through the giant outer core magma conviction currents? Is that an induced current, or its coming from other earth shields like those in the atmosphere, or from magmatic chemical reactions that produce electricity?
Is the solar magnetic field has its effect in inducing magnetism to planet earth and other planets , as most of them have a magnetic fields already? And is there any studies compared the earths magnetic field with that of other planets in our solar system?
We know that iron magnet loses its magnetic properties as it get heated, so how could the geodynmo keep his stable magnetized under thousands degrees of temperatures?
Best Regards.
Your welcome.
There are many things that are unknown. But the temperature in the outer core is not a big deal. The Earth is not a magnet, the Earth is an electromagnet, is the circulation of electrons in the outer core which produced the magnetic field and not a remanence in the core.
Regards