HR: 16:45h
AN: DI24A-04 INVITED    [Abstracts]
TI: A whole Earth dynamo model
AU: * Zhang, K
EM: kzhang@ex.ac.uk
AF: Department of Mathematical Sciences, University of Exeter, Exeter, EX4 4QE, United Kingdom
AU: Chan, K H
EM: mchan@hku.hk
AF: Department of Mathematics, University of Hong Hong, Hong Kong, Pokfulam, Hong Kong
AU: Liao, X
EM: xhliao@shao.ac.cn
AF: Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai, 200030, China
AB: The observations of modern magnetic, archaeomagnetic and paleomagnetic field of the Earth suggest a close correlation of the geomagnetic field with the structure of the Earth's lower mantle, pointing to the processes of a whole Earth dynamo. We report our progress on constructing a three-dimensional, whole Earth dynamo model based on an EBE (element-by-element) finite element method taking the full advantage of modern massively parallel computers. The dynamo model, driven by thermal or compositional convection, has been carefully compared with the well-known benchmark dynamo using spectral methods, showing a satisfactory agreement between two fundamentally different models. The whole Earth dynamo model consists of the four different zones: an electrically conducting solid inner core, a convective fluid outer core, an electrically conducting solid mantle and an exterior to the Earth. It is demonstrated that the numerical dynamo model can be effectively parallelized with nearly linear scalability on massively parallel computers. Since the model is based on a three-dimensional element-by-element finite element method, the physical properties of the Earth's mantle can be readily taken into account in the model. When the electrically conducting lower mantle has a heterogeneous electric conductivity, we reveal that the dynamo has to be time-dependent and the amplitude of the generated magnetic field is determined by the relative phase between the core magnetic field and the electrically heterogeneous lower mantle.
DE: 0545 Modeling (4255)
DE: 0560 Numerical solutions (4255)
DE: 1507 Core processes (1213, 8115)
DE: 1510 Dynamo: theories and simulations
SC: Study of the Earth's Deep Interior [DI]
MN: 2007 Fall Meeting