Spatio-temporal Chaos in Systems of Broken Symmetry

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This experimental condensed matter physics project deals with non-linear phenomena and patterns appearing in gases and fluids. The research is focused on the influence of broken symmetries on spatio-temporal chaos in dissipative pattern forming systems. As a prototype system the convection of a fluid layer with large lateral extent will be studied experimentally. First the coexistence region between thermal and shear driven instability will be investigated. Special attention will be given to the localized turbulent bursts and their relation to shear flow driven turbulence. Second the influence of spatial forcing on spatio-temporal chaos for convection in inclined and horizontal layers will be studied. Graduate students involved in the project receive training in fundamental experimental techniques, like high resolution digital image capture, digital image processing, precision temperature measurement and control techniques. In addition the graduate students will participate in the Cornell's interdisciplinary NSF IGERT program on Nonlinear Systems. This training will prepare them especially well for the challenging interdisciplinary workplace of the 21st century.%%%This experimental condensed matter physics project deals with non-linear phenomena and patterns appearing in gases and fluids. Ordered patterns are ubiquitous in nature. We can observe them on scales from a few centimeters in the ripples of the windblown sand to kilometers in cloud streets. In both cases the patterns are fueled by wind or by hot air rising from the earth's surface. Indeed such patterns occur in many driven systems. Usually those patterns are disordered in space and are changing constantly. We call such a behavior spatio-temporal chaotic. To date a unifying understanding of spatio-temporal chaos does not exist. However, an understanding of spatio-temporal chaos is very important since it may lead to the control of systems as complex as cardiac fibrillation and the generation of turbulence. We will investigate, how external modulations alter spatio-temporal chaos and turbulent bursts in convection of fluids. Graduate students involved in the project receive training in fundamental experimental techniques and cutting edge technologies. In addition the graduate students will participate in Cornell's interdisciplinary NSF IGERT program on Nonlinear Systems. This training will prepare them especially well for the challenging interdisciplinary workplace of the 21st century.