Directional soliton and breather beams

Solitons and breathers are nonlinear modes that exist in a wide range of physical systems. They are fundamental solutions of a number of nonlinear wave evolution equations, including the unidirectional nonlinear Schrödinger equation (NLSE). We report the observation of slanted solitons and breathers propagating at an angle with respect to the direction of propagation of the wave field. As the coherence is diagonal, the scale in the crest direction becomes finite; consequently, beam dynamics form. Spatiotemporal measurements of the water surface elevation are obtained by stereo-reconstructing the positions of the floating markers placed on a regular lattice and recorded with two synchronized high-speed cameras. Experimental results, based on the predictions obtained from the (2D + 1) hyperbolic NLSE equation, are in excellent agreement with the theory. Our study proves the existence of such unique and coherent wave packets and has serious implications for practical applications in optical sciences and physical oceanography. Moreover, unstable wave fields in this geometry may explain the formation of directional large-amplitude rogue waves with a finite crest length within a wide range of nonlinear dispersive media, such as Bose-Einstein condensates, solids, plasma, hydrodynamics, and optics.

Subjects

directional localizations

extreme events

nonlinear waves

solitons

DDC Class

530: Physik

600: Technik

620: Ingenieurwissenschaften

More Funding Information

A.C. acknowledges support from the Japan Society for the Promotion of Science (JSPS). A.V.B. acknowledges support from the Australian Research Council (Discovery Projects DP170101328). J.N.S. acknowledges an Engineering and Physical Sciences Research Council studentship (1770088). T.S.v.d.B. acknowledges a Royal Academy of Engineering Research Fellowship. N.A. acknowledges the Australian Research Council for financial support. M.O. has been funded by Progetto di Ricerca d’Ateneo Grant CSTO160004. M.O. was supported by the “Departments of Excellence 2018–2022” grant awarded by the Italian Ministry of Education, University and Research (L.232/2016). The experiments at the University of Tokyo were supported by KAKENHI of JSPS.

Lizenz

https://creativecommons.org/licenses/by/4.0/

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2019_PNAS_Directional Solitons and Breather Beams.pdf

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1.54 MB

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Directional soliton and breather beams