title: Switching dynamics and linear response spectra of a driven one-dimensional nonlinear lattice containing an intrinsic localized mode.
abstract: An intrinsic localized mode (ILM) represents a localized vibrational excitation in a nonlinear lattice. Such a mode will stay in resonance as the driver frequency is changed adiabatically until a bifurcation point is reached, at which point the ILM switches and disappears. The dynamics behind switching in such a many body system is examined here through experimental measurements and numerical simulations. Linear response spectra of a driven micromechanical array containing an ILM were measured in the frequency region between two fundamentally different kinds of bifurcation points that separate the large amplitude ILM state from the two low amplitude vibrational states. Just as a natural frequency can be associated with a driven harmonic oscillator, a similar natural frequency has been found for a driven ILM via the beat frequency between it and a weak, tunable probe. This finding has been confirmed using numerical simulations. The behavior of this nonlinear natural frequency plays important but different roles as the two bifurcation points are approached. At the upper transition its frequency coalesces with the driver and the resulting bifurcation is very similar to the saddle-node bifurcation of a single driven Duffing oscillator, which is treated in an Appendix. The lower transition occurs when the four-wave mixing partner of the natural frequency of the ILM intersects the topmost extended band mode of the same symmetry. The properties of linear local modes associated with the driven ILM are also identified experimentally for the first time and numerically but play no role in these transitions.
authors: Graduate School of Natural Science and Technology, Kanazawa University Kanazawa, Ishikawa 920-1192, Japan. msato@kenroku.kanazawa-u.ac.jp
authors: M
authors: M
authors: Sato
authors: S
authors: S
authors: Imai
authors: N
authors: N
authors: Fujita
authors: W
authors: W
authors: Shi
authors: Y
authors: Y
authors: Takao
authors: Y
authors: Y
authors: Sada
authors: B E
authors: BE
authors: Hubbard
authors: B
authors: B
authors: Ilic
authors: A J
authors: AJ
authors: Sievers
mesh_terms: D003198:Computer Simulation; D016014:Linear Models; D055617:Micro-Electrical-Mechanical Systems / Q000379:methods*; D017711:Nonlinear Dynamics; D009991:Oscillometry / Q000379:methods*