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Showing 1 to 9 of 9 for “"Geodynamo"”.
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Magnetic Stability Analysis for the Geodynamo
Kinematic dynamo modelling addresses the growth of magnetic fields under the action of fluid flow, effected in the geophysical case by the action of the convecting electrically conducting outer core and magnetic diffusion. In this study, we prescribe the flow to be stationary and geophysically …
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Development of a leaching procedure for isotopic study of metal/silicate partitioning experiments
… systems could be a contributor to Earth's geodynamo heating and affect Pb-Pb geochronology. Sixteen experimental iron/silicate samples were separated magnetically into iron and silicate fractions. Each fraction was leached with 2.5 M HCl, 10 M HCl, 10 M HCl at a higher temperature, and HF …
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Developing Archaeomagnetic Dating for Neolithic Scotland
… crucial information about the behaviour of the geodynamo. This thesis plays a vital role in expanding and developing the application of archaeomagnetic dating in the British Isles by studying fired archaeological material from Neolithic Scotland (4000 BCE – 2500 BCE). The aim was to use …
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Structure of the earth’s topmost inner core from seismic waveform inversion
… process, which is the driving mechanism of the geodynamo and the Earth’s magnetic field. However, some key features of the inner core have not been well understood, such as the relation between velocity and attenuation structure, and the global pattern of the lateral variation. In this …
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Helical waves in Earth's outer core
… However, due to computational constraints, many geodynamo simulations lie in a regime where the convective structures have a moderate Rossby number. These simulations, that over-estimate the influence of nonlinear inertia, undergo an abrupt transition from a columnar flow structure with a …
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Convection and Magnetic Field Generation in Rotating Spherical Fluid Shells
… for extrapolation to realistic models of the geodynamo. Of particular interest are various types of oscillations of dipolar fields. In contrast to quadrupolar and hemispherical dynamos dipolar dynamos have been originally considered to be non-oscillatory. But the six different types of dipolar …
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Deciphering the thermal evolution of small planetary bodies.
… requiring a different dynamo mechanism to the geodynamo. However, previous studies into dynamo generation in this regime have largely been restricted to numerical models. In this work, I have used novel analogue experiments to identify the key physics involved in inwards crystallization in …
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Box-Simulationen von rotierender Magnetokonvektion im flüssigen Erdkern
… magnetischem Fluss. Ein Mean-Field Modell des Geodynamos wurde konstruiert, das auf dem α-Effekt basiert, wie er aus den Box-Simulationen berechnet wurde. Für eine äußerst beschränkte Klasse von radialen α-Profilen weist das lineare α^2-Modell Oszillationen auf einer Zeitskala auf, die durch …
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Direction and intensity of Earth's magnetic field at the Permo-Triassic boundary
… and are explained by instabilities of the geodynamo after the reversal. However, VGPs associated with post-transitional excursions usually reach positions similar to those occupied by VGPs during the transition. In contrast to such "rebound" effects, the excursion-related VGPs of this …