Localized Instability on the Route to Disorder in Faraday Waves

Itamar Shani, Gil Cohen, and Jay Fineberg

 

The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel

(Received 8 December 2009; published 7 May 2010)

 

We experimentally investigate how disorder comes about in parametrically excited waves on a fluid  surface (Faraday waves). We find that the transition from an ordered pattern to disorder corresponding to ‘‘defect-mediated turbulence’’ is mediated by a spatially incoherent oscillatory phase. This phase consists of highly damped waves that propagate through the effectively elastic lattice defined by the pattern. They have a well-defined frequency, velocity, and transverse polarization. As these waves decay within a few lattice spaces, they are spatially and temporally uncorrelated at larger scales.