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Symposium
Stephen
Morris
Structure
from Instability: Nonlinear Patterns in Nature and the Laboratory
Presented
Saturday May 11th at 3 pm
Nature
is full of robust, self-organized structures; think of ripples
on wind blown sand, stripes on zebras, convection cells in
miso soup and surface waves on the coffee in a vibrating cup.
These organized structures develop and evolve in open, driven
systems. They thus evade the tedious requirement of the Second
Law of Thermodynamics, which demands that entropy (disorder)
must always increase in a closed system. On the contrary,
in open systems the tendency is toward complexity, ordered
structures and chaotic time evolution. This order is accompanied
by the production of entropy which is exported from the system
(you are doing this right now, as you read these words and
digest your lunch). Most simple self-organized patterns emerge
as a result of some sort of instability and its subsequent
nonlinear evolution. The standard laboratory example is convection,
the regular cellular flow of a fluid heated from below.
Under controlled conditions, strikingly ordered convection
patterns resembling perfect crystals can be observed. When
driven sufficiently hard, a convection pattern may exhibit
spatio-temporal chaos. This form of chaos is far more complex
than the garden variety found in simple low-dimensional systems
and is more representative of the kind of chaos most often
seen is Nature. In this talk, I will describe many natural
and laboratory examples of pattern formation and also attempt
some live demonstrations.
Stephen
Morris - Biography
Stephen Morris is an Associate Professor of Physics at the
University of Toronto. His interests range over many areas
of nonlinear self-organization and pattern formation in nonequilibrium
systems.
smorris@physics.utoronto.ca
http://mobydick.physics.utoronto.ca
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