MadSci Network: Earth Sciences

Re: Can I measure heating of earth's core due to solar wind/magnetic field/CME?

Date: Sun Jan 9 17:11:03 2005
Posted By: David Dunbar, Staff, Geophysics, GeoCenter, Inc.
Area of science: Earth Sciences
ID: 1103036331.Es


You are proposing a rather difficult project. A method for developing a
theoretical estimate of how the energy from a magnetic storm is split
between the core and the magnetosphere is not obvious. The studies of
magnetic storms I have found all pretty much ignore the core. While a
magnetic storm can create a million ampere “Ring Current” in the Van Allen
Belts and raise the ion temperature thousands of degrees, it is pretty thin
stuff up there. Dumping the same amount of energy into the core would
hardly change the temperature at all.

Your question does touch on why the Earth has a magnetic field at all.
Glatzmaier and Roberts’s papers on the geodynamo model produce a self
sustaining magnetic field that depends on a differential rotation of the
inner core and the rest of the Earth, convection currents in the outer core
and variable heat flow from the core to the mantle. The differential
rotation has been observed in seismic studies. 

Your second question is not much easier. There have been a number of papers
written attempting to reconcile thermodynamic theory with seismic velocity,
gravity and heat flow measurements. There is only a rough consensus on the
relative contributions of accretion energy and radioactive heat production.
The distribution (location) of the radioactive heat production differs
considerably between models. Different models disagree as to whether the
mantle convects from core to Moho in a single zone or at least two zones.
If there is a single zone the mantle will overturn in about 300 million
years. The short answer to your second question is hundreds of millions of

There are quite a few web sites devoted to the nature of the structure of
the Earth and it’s magnetic field. A disturbing number of them are
nonsense. A few web sites that may be of interest are,,,,,


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