HR: 16:10h
AN: GP32B-01 INVITED     [PDF]
TI: Progress Towards Understanding the Geodynamo from Observations and Numerical Models
AU: * Bloxham, J
EM: jeremy_bloxham@harvard.edu
AF: Harvard University, 20 Oxford Street, Cambridge, MA 02138 United States
AB: The new generation of magnetic field satellites currently in orbit hold enormous promise for understanding the generation of the Earth's magnetic field. These new data, together with earlier observations, and in combination with numerical models of the geodynamo, are enabling new insights into the dynamo process. Our approach aims to dissect the full range of behavior of the field that is observed: from high-latitude concentrations of flux that persist, at least in the time-average, over periods of several million years, to magnetic jerks, abrupt changes in the field on a timescale of a year or less. We describe a simple dynamical model of the core consistent with these observations. A number of key questions remain. How do reversals fit into this model? Are they simply a more extreme manifestation of secular variation, or do they require some separate explanation? How do we account for the different field morphologies and range of magnetic field strengths observed in the Solar System?
DE: 1510 Dynamo theories
DE: 1535 Reversals (process, timescale, magnetostratigraphy)
DE: 1545 Spatial variations (all harmonics and anomalies)
DE: 1560 Time variations--secular and long term
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2003 Fall Meeting