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Etude théorique et numérique de processus de retournement temporel.

Chokri Ben-Amar 1, 2
2 POEMS - Propagation des Ondes : Étude Mathématique et Simulation
CNRS - Centre National de la Recherche Scientifique : UMR7231, UMA - Unité de Mathématiques Appliquées, Inria Saclay - Ile de France
Abstract : The ability to focus the acoustic or electromagnetic energy both spatially and temporally in recent years is a subject of research interest because of the diversity and importance of applications. In the telecommunications sector, particularly in underwater acoustics, and mobile telephony in the wireless local area networks, one of the major challenges is to find techniques to deliver secure the greatest possible amount of information between a transmitter and different user through the use of acoustic or electromagnetic waves. These waves are likely to be reflected several times between the transmitter and the receiver given the multitude of obstacles encountered during the propagation in the areas concerned. These barriers may be the walls of buildings, cars or furniture in the case of mobile or interfaces between water and air or between water and the seabed in the case of underwater acoustic Navy. One of the questions posed by researchers in this field is to determine under what conditions multiple scattering can positively affect the concentration of energy at the receiver. Other applications include the field of imaging and medical therapy. Examples visualize certain organs or body tissues by ultrasonic waves (frequency range 1 MHz to 10 MHz μ). It also seeks to detect, locate and destroy kidney stones and tumors of the breast or brain concentration of ultrasonic waves of a fa con noninvasively. The scope of applications extends to nondestructive testing of materials, attention to the observation of irregularities in the metals or a geophysics for oil. We propose here to give different models of time reversal and to study and simulate their focusing properties. After having initially said the general principle of time reversal and different approaches to this technology, we describe more precisely the particular context of our study.
Mots-clés : Retournement temporel
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Chokri Ben-Amar. Etude théorique et numérique de processus de retournement temporel.. Mathématiques [math]. Ecole Polytechnique X, 2007. Français. ⟨pastel-00002944⟩

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