I\'m interested in getting a basic physical understanding of how Earth\'s magnet

Question

I'm interested in getting a basic physical understanding of how Earth's magnetic field is generated. I understand that it's a "dynamo" type of effect, driven by convection currents in the molten outer core. These currents cause charges to move, and this generates the field.

However, what I can't find a good explanation of is why there is a separation of charges in the first place. Presumably, moving neutrally charged molten iron would have the same effect as moving any other neutrally charged thing, i.e. it wouldn't create a field. And presumably, if the fluid wasn't moving then it would become neutral pretty quickly, since molten iron is a good electrical conductor.

So am I right in thinking that the charge separation is the result of positive feedback, in that an intial deviation from neutrality would generate a field, and this would (somehow) cause a greater separation of charges, resulting in a kind of self-maintaining charge separation? Or is there another explanation?

In either case, does anyone know of a good resource that explains the basic principles in physical terms? I know that the interior dynamo is a very complex phenomenon, but I'd like something that gives a good physical picture of how the electromagnetic and fluid dynamical phenomena interact, rather than diving straight into partial differential equations.

Explanation / Answer

According to Wikipedia the magnetic field is indeed the result of feedback. Actually the Wikipedia article is very good so I'm not sure how much there is left to say. The convection currents from the inner core outwards get bent onto spirals by the coriolis effect of Earth's rotation, and this gives a geometry where the magnetic field and electric currents sustain each other.

Re Lubo

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.