Investigations of the Geodynamo

Harvard University, Cambridge MA

Investigators

Abstract

Understanding the origin of the Earth's magnetic field and predicting its future evolution is one of the key problems in the Earth sciences. While it is nowadays almost universally accepted that the magnetic field is maintained by hydromagnetic dynamo action in the Earth's fluid, predominantly iron, outer core, the details of that process remain very poorly understood. This project has the following specific aims: 1. Investigation of the basic underlying mechanisms of magnetic field generation in recent numerical models of the geodynamo. 2. Investigation of the parameter regime of numerical dynamo models, seeking in particular to further our understanding of the role of inertial and viscous effects on the dynamo. 3. Investigation of thermal core-mantle interactions and their role in controlling the morphology of the main field and its secular variation. 4. Investigation of the effect of inner core gravitational coupling on the geodynamo. 5. Analysis of features observed in maps of the magnetic field at the core-mantle boundary using a numerical dynamo model. 6. Analysis of the frozen flux approximation, the assumption under which on sufficiently short timescales the magnetic field can be considered to be frozen into the fluid. 7. Dynamo code development, including development of a distributed memory version of the code suitable for running on a network of commodity-hardware based machines in order to take advantage of the performance-cost ratio of such hardware. The results of this work will be disseminated not only through traditional channels of scientific publication but additionally through non-traditional channels television documentaries to ensure dissemination beyond the research community. Additionally, the results will be incorporated into the Principal Investigator's teaching materials.