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Magnetostrophic Flow in Experiments and the Core of the Earth

Final Report Summary - MFECE (Magnetostrophic Flow in Experiments and the Core of the Earth)

The Earth’s core spins incredibly fast and generates Earth’s magnetic field.
Geophysicists strive to understand the physics of this process. By using computer models, we can recreate the force balance taking place within the core, and the mechanisms whereby energy is transformed into electrical currents and hence into magnetic fields. We have achieved a new class of models in which the fluid has a viscosity (runniness) equivalent to that of water. This is more realistic. Previous models used fluids whose viscosity was more like treacle, or even worse, pitch undergoing solid-state creep.

We are underway in our quest to understand, for example, what overall field strength will develop in different planetary bodies. This may elucidate, for example, why Jupiter has a strong field while Mercury has a week field.

We have built a mechanical device that is unique in the world whose purpose is to check these types of results in the laboratory. This device spins faster than the closest machine in design elsewhere in the world, and it can be subjected to stronger magnetic fields than is elsewhere possible. Preliminary tests of the device show its performance, with rotation up to 7,000 revolutions per minute. This device required special materials (Titanium), since it develops accelerations that are some tens of thousands times the strength of gravity on Earth.

A second achievement is that we have shown how to marry data together with computer models in an activity call data assimilation. This is akin to the technique used for weather forecasting, and can lead to more accurate models of the evolution of the Earth’s magnetic field some decades into the future.