SYD-UNSW Joint Colloquium : Friedlander -- Active Scalar Equations and a Geodynamo Model

This is the first talk of the colloquium double-header. 

The second talk is announced at

http://www.maths.usyd.edu.au/s/scnitm/zhangou-SYD-UNSWJointColloquium-J

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Speaker: Prof. Susan Friedlander (USC)

http://cams.usc.edu/~susanfri/

Time: Friday, Nov. 30, 2--3PM

Room: Chemistry Lecture Theatre 2

Lunch plan: meet near Level 2 entrance to Carslaw Building around 1PM. 
The lunch would be at Law Annex Cafe with reservation at 1:05PM. 

Please keep in mind that our schedule would be a little tight with 
Algebra Seminar finishing at 1PM and the first colloquium talk starting 
at 2:05PM.  

Refreshments would be provided by the school in the common room on 
Level 7 around 4PM. 

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Title: Active Scalar Equations and a Geodynamo Model

Abstract: we discuss an advection-diffusion equation that has
been proposed by Keith Moffatt as a model for the Geodynamo.
Even though the drift velocity can be strongly singular, we
prove that the critically diffusive PDE is globally well-posed.
We examine the nonlinear instability of a particular steady
state and use continued fractions to construct a lower bound
on the growth rate of a solution. This lower bound grows as
the inverse of the diffusivity coefficient. In the Earth’s
fluid core this coefficient is expected to be very small.
Thus the model does indeed produce very strong Geodynamo action.

This work is joint with Vlad Vicol.

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Joint Colloquium web site: 

http://www.maths.usyd.edu.au/u/SemConf/JointColloquium/index.html