Synonyms
Geodynamo
Definition
Dynamo. Process for generating electrical current and magnetic field by electromagnetic induction in a moving conducting medium.
Geodynamo. Dynamo process in the fluid outer core that generates Earth’s main magnetic field.
Introduction
It has been firmly established that the geomagnetic field must be generated by a magnetohydrodynamic dynamo operating in the Earth’s outer core. Thermal and compositional buoyancy forces drive a convective circulation of the liquid iron alloy. Assuming that a magnetic field is present, electrical currents are induced in the moving fluid. When the magnetic field associated with these currents has the strength and geometry that is suitable for the induction process and no external source for the field is required, this is called a self-sustained dynamo. The first approximation of the Earth’s core is a sphere with uniform electrical conductivity, in contrast to technical dynamos, where the currents are guided by a highly...
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Christensen, U.R. (2011). Core Dynamo. In: Gupta, H.K. (eds) Encyclopedia of Solid Earth Geophysics. Encyclopedia of Earth Sciences Series. Springer, Dordrecht. https://doi.org/10.1007/978-90-481-8702-7_38
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