How does Earth sustain its Mag Field?

[morenogabr]

Anyone want to try explaining Dynamo Theory to a 2nd year astrophy undergrad? Short and simple will do...

 

[Chronos]

The Earth rotates and has a molten, metallic [electrically conductive] core.

 

[morenogabr]

so what is it about the Earths rotation that induces the current in this conductive core?

 

[Denton]

I do believe the core, since it is molten and conductive has a large number of free electrons moving around in it, and moving charges give rise to magnetic fields.

 

[Andre]

It's thought that convection cells in the fluid outer core generate strong magnetic fields, but the different adjacent cells are assumed to counter rotate, almost cancelling out each others field. Only a residual field remains that can collapse or reverse depending on changes in the core convection cells.

That's the abstract of this:

http://www.psc.edu/science/glatzmaier.html

Better post these things in the Earth Science forum.