Experimental Investigation of the Transition to Spatiotemporal Chaos with a System-Size Control Parameter

摘要

Using a localized laser-heating method to allow the use of system size as a control parameter, we experimentally investigate, using liquid-crystal electroconvection with soft boundary conditions, the onset of spatial temporal chaos (STC) with increasing system size. We find that temporal periodicity is significantly quenched as the system size increases. The increase of the fourth moment (kurtosis) of the temporal Fourier transform provides a very useful quantitative measure of the loss of temporal periodicity (hence the onset of STC) as the pattern size increases, and also provides a simple means for determining a natural chaotic length scale. This length scale is comparable to the length of vertical rows observed in the original pattern. Our experiments, thus, imply that there are well-defined building blocks, which in our case are easily visualized, that control the dynamics in STC liquid crystal convection. The results of our experiments appear to be consistent with the conclusions of recent STC computer simulations carried out by Fishman and Egolf.