A detailed numerical study of the long time behaviour of dispersive shock waves in solutions to the Kadomtsev–Petviashvili (KP) I equation is presented. It is shown that modulated lump solutions emerge from the dispersive shock waves. For the description of dispersive shock waves, Whitham modulation equations for KP are obtained. It is shown that the modulation equations near the soliton line are hyperbolic for the KPII equation while they are elliptic for the KPI equation leading to a focusing effect and the formation of lumps. Such a behaviour is similar to the appearance of breathers for the focusing nonlinear Schrödinger equation in the semiclassical limit.

%B Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences %V 474 %P 20170458 %G eng %U https://royalsocietypublishing.org/doi/abs/10.1098/rspa.2017.0458 %R 10.1098/rspa.2017.0458 %0 Journal Article %J COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING %D 2018 %T NURBS-SEM: A hybrid spectral element method on NURBS maps for the solution of elliptic PDEs on surfaces %A Giuseppe Pitton %A Luca Heltai %B COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING %V 338 %P 440–462 %G eng %U https://arxiv.org/abs/1804.08271 %R 10.1016/j.cma.2018.04.039 %0 Report %D 2016 %T Non-linear Schrödinger system for the dynamics of a binary condensate: theory and 2D numerics %A Alessandro Michelangeli %A Giuseppe Pitton %X We present a comprehensive discussion of the mathematical framework for binary Bose-Einstein condensates and for the rigorous derivation of their effective dynamics, governed by a system of coupled non-linear Gross-Pitaevskii equations. We also develop in the 2D case a systematic numerical study of the Gross-Pitaevskii systems in a wide range of relevant regimes of population ratios and intra-species and inter-species interactions. Our numerical method is based on a Fourier collocation scheme in space combined with a fourth order integrating factor scheme in time. %G en %U http://urania.sissa.it/xmlui/handle/1963/35266 %1 35572 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-01-16T12:09:24Z No. of bitstreams: 1 SISSA_preprint_63-2016-MATE_Michelangeli-Pitton-2016.pdf: 6158349 bytes, checksum: ab11de2762ff510e6833474d0688a8b4 (MD5)