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Accueil du site > Évènements > Séminaires > Séminaires IRPHE > Archives IRPHE > 2019

Mardi 9 Juillet 2019 / IRPHE

publié le

Séminaire exceptionnel IRPHE

Extreme spatial clustering by fractal catastrophes

Orateur : Bernhard Mehlig University of Gothenburg

Abstract : We analyse the spatial inhomogeneities (’spatial clustering’) in the distribution of inertial particles accelerated by a space-time dependent random force. To quantify spatial clustering, the phase-space dynamics of the particles must be projected to configuration space, resulting in mathematical catastrophes (’caustics’) whose quantitative contribution to spatial clustering is not understood. We show how to solve this problem by projecting the phase-space finite-time Lyapunov exponents (FTLEs) to configuration space. Applying our method in one spatial dimension, we find that in the long-time limit ’fractal catastrophes’, caustics that arise from the projection of a dynamical fractal attractor, make a distinct and universal contribution to the distribution of spatial FTLEs. This contribution gives rise to an extreme form of spatial clustering, and breaks a fluctuation relation for white-in-time Gaussian force fields.

Date et lieu : mardi 9 juillet 2019 à 11h dans la salle de séminaire IRPHE

Voir en ligne : la page personnelle de l’orateur