Localized spatiotemporal chaos in surface waves

A route to spatiotemporal chaos (STC) is identified in parametrically forced surface waves in which strongly disordered fluctuating domains coexist with textured stripes. The chaotic domains of this mixed state nucleate via instability at the most strongly curved regions of the stripe pattern. The area covered by the STC grows with the imposed acceleration, and fills all regions where the local curvature exceeds an E-dependent critical curvature. The striped domains within the mixed state are also distorted by a secondary oscillatory instability at moderate viscosity.