About the Project
"Background
A proper understanding of how the geomagnetic field is generated in Earth’s liquid core, by the so-called geodynamo, remains one of the greatest outstanding problems in Earth science. The principal difficulty is that the core is far too remote to be probed directly; scientific knowledge has advanced through exploiting the limited set of observations and computer simulations of the Earth’s core. Of significant importance is that observations from Earth’s surface can only constrain the structure of the magnetic field at the edge of the source region: the structure of the field within the core is unknown.
From a mathematical standpoint, on medium to long time scales, the core can be realistically modelled as a constrained dynamical system. Such an idea may be more familiar in mechanical systems such as (industrial) robots, which are often modelled as constrained dynamical systems: the parts move under the force exerted by motors according to the laws of mechanics under the constraint that the rods and other elements do not extend or compress. The rods in such systems can also be considered as springs in the limit that the stiffness constant goes to infinity. Specialized numerical methods are required when simulating such systems.
The focus of this project is to consider the Earth’s core as evolving under the control of a system of constraints, called the Taylor constraints, which stem from the dominance of the rotational forces inside the core. In addition, recent evidence from seismology alongside studies of the material conditions thought to prevail within the core, further suggest the outermost part of the core is stratified. This leads to a further set of Malkus constraints, that add to the Taylor constraints, which the internal magnetic field must satisfy. The goal of this project is to construct both static and dynamical models of the Earth’s magnetic field that satisfy this large set of constraints.
Realistic modelling of the large-scale background structure of the internal magnetic field may shed light on fundamental features which are still unexplained, such as why the Earth’s field is predominantly aligned with the rotation axis, and how the magnetic field undergoes global reversals.
Training
The student will learn both the theory and computational techniques required to model the Earth’s core, and will have access to a broad spectrum of training workshops put on by the Faculty that include an extensive range of workshops in numerical modelling, through to managing your degree, to preparing for your viva (http://www.emeskillstraining.leeds.ac.uk/).
The student will be a part of the deep Earth research group, a vibrant part of the Institute of Geophysics and Tectonics, comprising staff members, postdocs and PhD students. The deep Earth group has a strong portfolio of international collaborators which the student will benefit from.
Although the project will be based at Leeds, there will be opportunities to attend international conferences (UK, Europe, US and elsewhere), and potentially collaborative visits within Europe.
Requirements
We seek a highly motivated candidate with a strong background in mathematics, physics, computation, geophysics or another highly numerate discipline. Knowledge of geomagnetism is not required, and training will be given in all aspects of the PhD.
For further information please contact Phil Livermore ([Email Address Removed]) or Jitse Niesen ([Email Address Removed]).
Other opportunities
The Deep Earth Research Group in Leeds (http://www.see.leeds.ac.uk/research/igt/deep-earth-research/) is one of the largest groups of scientists studying the structure and dynamics of Earth’s core and mantle in the world. Dr Livermore is interested in the dynamics of the core and geomagnetism. Please contact him ([Email Address Removed]) to discuss further PhD opportunities."
http://www.nercdtp.leeds.ac.uk/projects/index.php?id=500
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