Séminaire de l’équipe MCS
Responsables : M. DARBAS, E. AUDUSSE
Lundi 13 avril 2026
11:00 Marie Touboul (Poems CNRS-INRIA-ENSTA) 
Résumé
Wave propagation across time-varying interfaces
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13The metamaterial field has strongly expanded recently with the introduction of the time variation of the mechanical properties referred to as Space-Time metamaterials and which offers new possibilities for waves control. While research has largely focused on modulated materials with bulk properties dependent on both space and time, we rather focus in this work on time-modulated interfaces. More precisely, we consider wave propagation in a 1D medium containing interfaces whose jump conditions are modulated in time. In the case of a single interface, properties of the scattered waves are investigated theoretically and numerically: energy balance, generation of harmonics, impedance matching and non-reciprocity. In the case of a periodic network, low-frequency homogenization is performed for different regimes of the frequency of modulation. When the frequency of modulation is low or moderate, standard homogenization is applied and ends up with a reciprocal effective model with time-dependent effective coefficients. For time-periodic modulations, the occurrence of gaps in wavenumber is illustrated. In the regime of high-frequency modulation, homogenization with a fast-time scale leads to an effective model with constant effective parameters but with a Willis coupling term breaking reciprocity. Comparisons with time-domain simulations illustrate the findings.
