Just read this article (The Dynamo in The Corn Field) over at Space Daily.

I've been imagining how to conduct this sort of experiment ever since my first paleo-magnetism class where we discussed at length the geologic origins of the earth's magnetic field. I've long been confused by what fluid to use until I started hearing about using sodium a few years ago. I didn't know that this was going on though. I'm only just starting to learn about the Madison Dynamo Experiment.

On first impression, I have two thoughts.

The first is the use of propellers to drive the metal. I had envisioned inducing differential rotation to the inner and outer spheres to induce frictional linear flow of the fluid. Which has been done with rotating cylinders. I saw it years ago on a NOVA, or some such show, that dealt with chaos and fractals. Anyone remember that? I don't know if anyone has tried a similar experiment with liquid sodium.

The second problem I have wondered about is overcoming the effects of gravity on the spinning dynamo. This seems to be an experiment that could also be conducted in a low or no gravity environment.

Okay, three thoughts: This is really cool.