How does a global pole reversal occur?

Question

How do the Earth's poles reverse? I've heard that there have been 5 pole reversals since its beginning, but how did they happen? Does it take a large event to take place to make this happen? How does its field collapse? Is it a shift in potential, or does it just ware away after a while, or what? I can't find anything that explains it.

Does it have to do with the general qualities of capacitance and inductance that the earth has?
I'd say it had more to do with inductance actually, but how does the earth's magnetic field exist in the first place?

Answer 1

Although this is a popular subject with some 'alternative' groups....
Geological information states that the poles do not 'wander'; reverse, or move.
When geomagnetic measurements were begun it showed different positions for the magnetic poles. But, what eventually this was shown to be due to plate tectonics...IOWs....the poles didn't move...the continents did...
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Answer 2

Most of us like stability in our lives, especially when it comes to planet-wide phenomena, such as the daily appearance of the sun or the periodic change of season. So it can be unsettling to learn of global phenomena that are inherently unstable, unpredictable. Such is the case with the Earth's magnetic field. Every so often, our planet's magnetic poles reverse polarity (see When Compasses Point South). Compass needles have always pointed north; in a reversal, they would point south.

You could perhaps take comfort in the knowledge that these reversals happen infrequently—on average every 250,000 years—but maybe not when you consider that it's been over 700,000 years since the last reversal, and the next one may be currently underway.

The Earth's magnetic field is created deep within our planet's outer core through a complex, self-sustaining interaction known as the "geomagnetic dynamo" (see What Drives Earth's Magnetic Field?). In the 1980s, Gary Glatzmaier, now at the University of California, Santa Cruz, and Paul Roberts of the University of California, Los Angeles, began work on a computer model that simulates this interaction. By 1995, they had created a model that not only created a self-sustaining magnetic field (the first to do so), but after simulating the passage of 36,000 years, the field it generated spontaneously flipped.

Here, view the animation generated by the Glatzmaier-Roberts computer model and see what happens during a reversal. —Rick Groleau
http://www.pbs.org/wgbh/nova/magnetic/reversals.html

Answer 3

I have not heard any theories as to how polar reversals occur, so I cannot answer your question. When the field collapses, secondary dipoles not located near the axial poles assume the role of the primary dipoles until the reversal is complete. This process takes tens of thousands of years to complete. I don't know where you heard that there have been only 5 reversals "since its beginning". Polar reversals is most easily seen in basaltic oceanic crust, since basalt contains the mineral magnetite and oceanic crust is continuously made at mid-oceanic ridges. The oldest oceanic crust is 180 million years and polar reversals have been determined to occur (an average) on the order of hundreds of thousands. For simplicity, I will chose an average of 180,000 years, giving a continuous record of 100 reversals. Going to a time when the molten Earth solidified (3.9 billion years ago) gives over 20,000 reversals, assuming the average remained constant over geologic history and that reversals started soon after the Earth solidified.

Answer 4

I would suppose any theory is as valid as any other since there is no evidence of any type except particles embedded in rock that are aligned against the current field direction. In theory if a inductive magnetic field collapses it could reestablish itself with a reversed polarity. Giving that the magnetic field shields us from highly destructive particles and the reversals are not connected to mass extinction events it is a given that it is a relatively quick event.