Re: Earth's Magnetic Field

[paul o johnson <pojhome@FLASH.NET>]

William Beaty wrote:

> The computer simulations in that SciAm article depict the motion as a big
> nasty mess of 3D vortices.  Imagine a hot-tub with several turbulent water
> jets.  Imagine a bunch of smoke-rings which are colliding and
> interweaving.

In which the water is moving relative to the tub and the smoke is moving relative
to the floor. So the Earth's fluid outer core is moving relative to what?

> A Wimshurst electrostatic generator gives a good analogy: if there are no
> ambient e-fields present, then the Wimshurst generator will never develop
> a high voltage no matter how long we turn the crank.  But if a small
> e-field hits the device, it causes a breaking of symmetry and the machine
> can then ramp up its voltage exponentially until it is limited by corona
> leakage.  A shorted-out self-exciting dynamo is similar: we can crank it
> forever, but if there is zero ambient b-field, then the generator won't
> run.  If a small ambient b-field is present, then the generator can create
> a small current, which makes a bigger b-field, which generates a larger
> current, and the current grows exponentially until it is limited by
> resistive losses.

And to hell with Lenz's law, huh?

Please bear with me, William; your explanations are slowly opening the door to
understanding for me. But each answer generates further questions.

poj