[GTP] GTP Seminar-Vadim Uritsky--University of Calgary

[Silvia Gentile]

Event Decomposition of Intermittent Spatiotemporal Patterns in Nature 
and Simulations
Vadim Uritsky
Physics and Astronomy Department, University of Calgary


Abstract:

Critical avalanches of instabilities in sandpile models and bursty 
localized energy dissipation in high-Reynolds number fluids are 
paradigmatic examples of multiscale intermittency in nonlinear systems 
with spatially extended degrees of freedom. In this talk, I will present 
a novel approach for dealing with these and other manifestations of 
complex intermittent behavior which is abundant in nature and 
simulations. The approach is based on spatiotemporal decomposition of a 
continuous time-dependent turbulent field (either numerical or 
observational) into a collection of discrete dissipation events composed 
of contiguous spatial regions of propagating activity. The developed 
method provides a detailed representation of the intermittent component 
of the studied dynamics including its most essential physical and 
topological parameters, while significantly reducing the amount of 
stored information. It also allows to selectively address different 
classes of intermittent disturbances based on a flexible set of 
filtering criteria. The efficiency of the proposed approach will be 
illustrated by several space physics applications (bursty dissipation in 
the solar corona, particle precipitation in the auroral zone, localized 
magnetic reconnection in a driven plasma sheet), and its relevance to 
ongoing NCAR projects will be discussed.



Monday, January 28, 2008
Center Green Laboratory 1, Room 2126
Lecture 2:30pm
(Coffee and tea at 2:15pm)