Excitation of travelling multibreathers in anharmonic chains

[摘要] We study the dynamics of the externally forced and damped Fermi-Pasta-Ulam (FPU) 1D lattice. The forcing has the spatial symmetry of the Fourier mode with wavenumber p and oscillates sinusoidally in time with the frequency omega. When omega is in the phonon band, the p-mode becomes modulationally unstable above a critical forcing, which we deter-mine analytically in terms of the parameters of the system. For omega above the phonon band, the instability of the p-mode leads to the formation of a travelling multibreather, that, in the low-amplitude limit could be described in terms of soliton solutions of a suitable driven-damped nonlinear Schrodinger (NLS) equation. Similar mechanisms of instability could show up in easy-axis magnetic structures that are governed by such NLS equations. (C) 2002 Elsevier Science B.V. All rights reserved.

[发布日期] 2002-08-01

[效力级别]  Proceedings Paper

[关键词] FPU lattices;breathers