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October 5-6, 2001

Material from Talks

Raymond Hide (Oxford University)

The Spinning Earth

Possibly the most striking feature of the long-term behaviour of the main geomagnetic field are the very long (~ 30 MYr) intervals when no polarity reversals seem to have occurred. Generic nonlinear processes in self exciting dynamos include the redistribution of kinetic energy by Lorentz forces. According to recent work on certain Faraday disk dynamos, under the simplest boundary conditions this process can give rise to ``nonlinear quenching'' of reversals, thereby providing a possible theoretical basis for interpreting superchrons and other features of the reversal timeseries. It is of general theoretical interest to study nonlinear quenching of fluctuating solutions of other autonomous sets of nonlinear ODE's, such as the Lorenz and Roessler sets.

Anatoli L. Levshin (Department of Physics, University of Colorado at Boulder) levshin@tinker.colorado.edu

Present-day Surface Wave Seismology

Joint work with Michael Ritzwoller.

In recent years surface waves have found wide applications in various seismological studies of a very different scale. We present a brief description of our recent results in regional surface wave tomography of continents, in applying these results for nuclear tests monitoring purposes, and in studying shear-velocity structure of soft sediments below sea bottom.

Misha Vishik Department of Mathematics (University of Texas at Austin Austin , TX 78712) vishik@mail.ma.utexas.edu

Some old and more recent results of the mathematical theory of an ideal incompressible fluid     Slides

We will start with the review of the classical existence theory for the Euler equations of an ideal incompressible fluid. These results obtained in the 1920s and 1930s still constitute the core of the theory. We will discuss the weak solutions in dimension 2 and some more recent uniqueness results. The ideas coming from Harmonic Analysis will be emphasized in this talk.

Material from Talks

Special Event: Vladimir Keilis-Borok 80th Birthday Festschrift

2001-2002 IMA Thematic Year on Mathematics in the Geosciences