Scheme: Wolfson Research Merit Awards
Organisation: University College London
Dates: Oct 2007-Sep 2012
Summary: My main research area is in the computer simulation of the properties of materials, including materials under the extreme conditions found in the Earh's core. My research last year involved the study of the transport properties of the Earth's core.
The Earth is cooling, and heat is transferred from the centre to the surface, and eventually lost in space. Heat is transferred through two main mechanisms: conduction and convection. Conduction is motionless, and is the mechanism through which the handles of a pan on fire get hot.
Convection instead involves motion: hot air raises because is less dense than cold air, and heat is transferred to the top of the atmosphere in the process.
In our recent research we found that the thermal conductivity of iron and iron alloys (the constituents of the Earth's liquid outer core) is a lot higher than previous estimates, and therefore heat transfer by conduction from the bottom of the core to the top of the core is much more efficient than previously thought.
This means that less heat is available to drive convection, the bodily motion of the outer core
fluid that is crucial for the continual generation of Earth's magnetic field. The vigor of convection and the strength of the magnetic field are both dependent on the heat available to drive convection: to sustain the same magnetic field with a higher thermal conductivity requires more energy to power the convection. The main energy source for core convection comes from cooling of the whole Earth, which leads to growth of the inner core due to freezing of the liquid iron alloy that comprises the outer core liquid. The amount of energy released depends on how quickly the core is cooling, which also controls how fast the inner core is growing. More energy requires a faster cooling rate, which leads to more rapid freezing, or in other words the inner core grows more quickly, which means that it is younger that previously thought because it has got to the present size in less time.
Scheme: University Research Fellowship
Dates: Oct 2000-Mar 2006
Summary: This project summary is not available for publication.