Nonlinearity in periodic media

The dynamics of the acoustic waves travelling through periodic structures show very special properties, e.g. anisotropic dispersion. In addition, when intense waves are considered, the interaction of nonlinear waves with the material dispersion lead to the emergence of a wide range of intrinsically nonlinear phenomena. I'm working in the existence of nonlinear localized waves in different media: supersonic excitations in cation lattices, solitons and nonlinear waves in layered acoustic media, sonic crystals and macroscopic lattices of oscillators.

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Nonlinear waves in phononic crystals

I'm studying nonlinear wave processes in spatially modulated media suh as multilayered acoustic media, phononic crystals or sonic crystals. The rich nonlinear dynamics of this system is characterized by its strong dispersion. Here, harmonic generation processes and its relation with its band structure are explored. We found that the nonlinear processes can be enhanced, strongly minimized or simply modified by tuning the material dispersion relation. Thus, the combined action of nonlinearity (harmonic generation) and periodicity (different propagation velocities and attenuation for the different harmonics) results in novel and unexpected phenomena with respect to the linear counterpart, and opens the door to new mechanisms of acoustic wave control and manipulation.

pdf link doi Asymmetric propagation using enhanced self-demodulation in a chirped phononic crystal
A. Cebrecos, N. Jiménez, V. Romero-García, R. Picó, V. Sánchez-Morcillo, L. García-Raffi,
AIP Advances, 6, pp 121601, (2016)

pdf link doi Nonlinear propagation and control of acoustic waves in phononic superlattices
N. Jiménez, A. Mehrem, R. Picó, L. M. García-Raffi, V. Sánchez-Morcillo,
Comptes Rendus Physique, 17 (5), pp 543 - 554, (2016)

pdf link doi Nonlinear self-collimated sound beams in sonic crystals
E. M. Hamham, N. Jiménez, R. Picó, V. Sánchez-Morcillo, L. G. Raffi, K. Staliunas,
Phys. Rev. B, 92, pp 054302, (2015)

Nonlinear waves in lattices

I'm also exploring intense nonlinear waves in lettices of coupled oscillators. An example are strain waves in a chain of cations coupled by realistic interatomic potentials. In this case, the nonlinear ionic interactions and lattice dispersion lead to the formation of supersonic kinks. These intrinsically-nonlinear localized dislocations travel long distances without changing its properties and explain the formation of dark traces found in muscovite-mica crystals.

pdf link doi Ultradiscrete kinks with supersonic speed in a layered crystal with realistic potentials
J. F. Archilla, Y. A. Kosevich, N. Jiménez, V. Sánchez-Morcillo, L. M. García-Raffi,
Phys. Rev. E, 91 (2), pp 022912, (2015)

pdf link doi Moving excitations In cation lattices
J. F. Archilla, Y. Kosevich, N. Jiménez, V. Sánchez-Morcillo, L. García-Raffi,
Ukranian Journal of Physics, 58 (7), pp 646-656, (2013)

pdf link doi Macroscopic acousto-mechanical analogy of a microbubble
J. Chaline, N. Jiménez, A. Mehrem, A. Bouakaz, S. D. Santos, V. Sánchez-Morcillo,
The Journal of the Acoustical Society of America, 138 (6), pp 3600-3606, (2015)

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