103. Currents that Generate the Earth's Magnetism
About "the currents responsible for the Earth's magnetic field lose energy to electric resistance", did you mean electric current? And how does the electric current being generated in the core?
Yes, I meant electric currents. As to how they are generated--it's a long story. This file is part of a collection of web pages "The Great Magnet, the Earth" giving a historical review of the Earth's magnetism, Its home page is
and the "dynamo mechanism" generating such currents is discussed in section 12 and beyond, and also in the technical review "A Millennium of Geomagnetism" included in the collection. Please, find your answer there!
I read the review you showed me and now understand about the generation of electricity.
How strong should the energy source be? You just wrote that the energy loss to electrical resistance is a very slow process.
And what do you mean by "any self-sustaining dynamo in the Earth's core cannot have an axis of symmetry"?
And lastly, why did you say that the energy source of Earth's core must also be able to drive motion?
I do not know how strong--experts in that area may be working on that, and I am not sure how well even they can specify it. People have used computers to simulate a convecting liquid core (with and without inner core, but with parameters different from those believed to exist--those may have to wait for better computers). Depending on the distribution of heat conductivity outside the core, they usually got "dynamo magnetic fields", sometimes with polarity reversals now and then, sometimes without.
The fact that a dynamo cannot be completely symmetrical was a mathematical property discovered by Thomas Cowling, and it complicated the mathematical handling of the dynamo problem. Cowling's theorem was published in the 1930s, and solutions for flows through magnetic configurations, which also generated the currents required for maintaining those same magnetic configurations--those were only derived by Stanislaw Braginsky around 1960 (and they turned out to be possible even with only slight lack of symmetry).
As for fluid motion, it is an essential component of the dynamo process--on the sun too, for instance. No believable mechanism for generating currents has been proposed in which there was no circulating flow
104. "Dead Zones" for radio signals (message in Spanish)
H a y u n m i t o u r b a n o e n M e x i c o , m i p aís :
H a y u n a z o n a e n D u r a n g o y C h i h u a h u a d e l q u e n o s a l e n n i e n t r a n c o m u n i c a c i o n e s .
E x i s t e e s t o a q uí