Experimental observation of a nonpitchfork acceleration instability in a nematic liquid crystal.

The velocity of domain walls caused by a symmetry-breaking instability is experimentally investigated for the case of electroconvection in a nematic liquid crystal. It turns out that the velocity increases linearly with the distance from the bifurcation creating the domains. This scaling behavior does not agree with the drift pitchfork bifurcation. It has, however, been predicted by a minimal model describing our scenario.