) to that of the surrounding pattern; a localized phase shift
is often called an arching in studies of two-dimensional systems.
The simulations show that the formation of phase bubbles is
triggered by undulation at the bottom of the layer on a
large length scale compared to the wavelength of the
pattern. Once formed, a phase bubble shrinks as if it had a
surface tension, and disappears in tens to hundreds of
cycles. We find that there is an oscillatory momentum
transfer across a kink, and the shrinking is caused by a net
collisional momentum inward across the boundary enclosing the
bubble. At increasing acceleration amplitudes, the patterns evolve into randomly
moving labyrinthian kinks (spatiotemporal chaos). We observe in the simulations
that f/3 and f/6 subharmonic patterns emerge as primary instabilities,
but that they are unstable to the undulation of the layer.
Our experiments confirm the existence of transient f/3 andf/6
patterns.Phys. Rev. E 65, 011301 (2002).