Geodynamo Models

I am currently working on physical models of the mechanism that produces the Earth's magnetic field. Geophysicists believe that the Earth's magnetic field is produced by a dynamo effect in the Earth's outer core. Several physical models exist of the phenomenon, but all have some problems. Those that accurately represent the geodynamo fail to exhibit a spontaneously reversing magnetic field.

The graph above represents the current evolution versus time for a Rikitake double-disc dynamo. Note that the field reverses polarity in a chaotic manner. The Rikitake dynamo is not regarded by most scientists as an accurate model of the Earth's core, but several modifications can be made to improve its accuracy. The data was obtained through a Burlisch-Stoer numerical solution to the four differential equations governing the behavior of the system.

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Dan Hennessy mailto:hennessy@ugcs.caltech.edu