Does Zonal Swishing Play a Part in Earth's Magnetic Field Reversals?

Zonal swishing in the Earth's outer core (Credit: Akira Kageyama, Kobe University)

Why does the Earth's magnetic field 'flip' every million years or so? Whatever the reason, or reasons, the way the liquid iron of the Earth's outer core flows – its currents, its structure, its long-term cycles – is important, either as cause, effect, or a bit of both.

The main component of the Earth's field – which defines the magnetic poles – is a dipole generated by the convection of molten nickel-iron in the outer core (the inner core is solid, so its role is secondary; remember that the Earth's core is well above the Curie temperature, so the iron is not ferromagnetic).

But what about the fine structure? Does the outer core have the equivalent of the Earth's atmosphere's jet streams, for example? Recent research by a team of geophysicists in Japan sheds some light on these questions, and so hints at what causes magnetic pole flips.

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Read the rest of Does Zonal Swishing Play a Part in Earth's Magnetic Field Reversals? (386 words)

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© Jean Tate for Universe Today, 2010. |
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Post tags: earth magnetic field, Earth's outer core, geomagnetic reversal, planet earth

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Full story at http://www.universetoday.com/2010/02/20/does-zonal-swishing-play-a-part-in-earths-magnetic-field-reversals/