A. Laporta et Cm. Surko, PHASE DEFECTS AND SPATIOTEMPORAL DISORDER IN TRAVELING-WAVE CONVECTION PATTERNS, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 56(5), 1997, pp. 5351-5366
Spatiotemporal disorder is studied in traveling-wave convection in eth
anol-water mixtures. Spectral measures of disorder, linear correlation
functions, and mutual information are used to characterize the patter
ns, and are found to give a weak indication of the level of disorder.
The calculation of the complex order parameter for experimental patter
ns is described. It is found that the ordering of the patterns is acco
mpanied by a dramatic change in the topological structure of the order
parameter. Specific arrangements of defects are found to be associate
d with the elements of traveling-wave patterns, and the net charge and
total number of defects is introduced as a measure of disorder in the
patterns. The coarsening of the patterns is marked by an accumulation
of net charge and a dramatic decrease in the number of defects. The p
hysical significance of the defects is discussed, and it is shown that
the phase velocity of the waves is lower in the vicinity of the defec
ts. The defect-defect correlation functions are calculated for the con
vection patterns. It is shown that the ordering of the patterns is clo
sely related to the apparent defect-defect interactions.