BEGIN:VCALENDAR VERSION:2.0 PRODID:-//wp-events-plugin.com//6.4.7.2//EN TZID:Europe/Paris X-WR-TIMEZONE:Europe/Paris BEGIN:VEVENT UID:0-761@lptms.universite-paris-saclay.fr DTSTART;TZID=Europe/Paris:20210202T110000 DTEND;TZID=Europe/Paris:20210202T120000 DTSTAMP:20210105T221421Z URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm s-phlam-lille/ SUMMARY:Séminaire du LPTMS : Pierre Suret (PhLAM - Lille) - LPTMS (100% on line seminar) - 2 Fév 21 11:00 DESCRIPTION:Integrable turbulence and soliton gas: experiments and theoreti cal approaches\nPierre Suret (PhLAM - Lille)\n\nOnline seminar --- Zoom Me eting ID: 996 1840 3246 -- Passcode: Ask L. Mazza or D. Petrov --\n\n\nExa ctly integrable partial differential equations (PDEs) such as the Korteweg -de-Vries (KdV) or the one-dimensional nonlinear Schrödinger equation (1D NLSE) can be studied in the framework of the Inverse Scattering Transform (IST). Integrable PDEs exhibit an infinite hierarchy of invariants that pr event the development of "standard" Wave Turbulence and energy cascade. De spite the existence of the IST technique\, there is no general theory desc ribing of the propagation of random waves in integrable systems such as 1D NLSE. For this reason\, Integrable Turbulence\, which deals with random fi elds\, has been recently introduced as a completely "new chapter of turbul ence theory" by V.E. Zakharov\, one of the creators both of the wave turbu lence theory and of the IST [1].\n\nSoliton gas (SG) is one example of int egrable turbulence. The concept of SG as a large ensemble of solitons rand omly distributed on an infinite line and elastically interacting with each other originates from the work of Zakharov [2]\, who introduced the kinet ic equation for a nonequilibrium diluted gas of weakly interacting soliton s of the KdV equation. Zakharov’s kinetic equation has been generalized to the case of a dense SG in Ref. [3].\n\nOptical fibers and 1D water tank s are very favorable experimental platforms for the investigation of integ rable turbulence and soliton gas (described by the focusing 1DNLSE). In th is talk\, I will present our recent experimental results obtained both in optical fibers and water tanks [4-6]. In the second part of my talk\, by u sing the famous example of the modulation instability\, I will show that S G is a promising model to describe the statistical properties of integrabl e turbulence. The spontaneous modulation instability (MI) also named “no ise-induced MI” arises when a plane wave is perturbed by noise in 1DNLSE . We will show that the long-term evolution of MI can be described by a ca refully designed SG [7].\n\n[1] V. E. Zakharov\, Stud. Appl. Math. 122\, 2 19 (2009)\n[2] V. E. Zakharov\, Sov. Phys. JETP 33\, 538 (1971)\n[3] G. El \, Phys. Lett. A 311\, 374 (2003)\n[4] A. Tikan\, S. Bielawski\, C. Szwaj\ , S. Randoux\, and P. Suret\, Nature Photonics 12\, 228 (2018)\n[5] A. E. Kraych\, D. Agafontsev\, S. Randoux\, and P. Suret\, Phys. Rev. Lett. 123\ , 093902 (2019).\n[6] P Suret et al. Phys. Rev. Lett. 125\, 264101 (2020)\ n[7] A Gelash\, D Agafontsev\, V Zakharov\, G El\, S Randoux\, P Suret\, P hys. Rev. Lett 123\, 234102 (2019)\n\n\n\n CATEGORIES:seminars LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n ° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0 END:VEVENT BEGIN:VTIMEZONE TZID:Europe/Paris X-LIC-LOCATION:Europe/Paris BEGIN:STANDARD DTSTART:20201025T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET END:STANDARD END:VTIMEZONE END:VCALENDAR