P. Alstrom et al., RELATIVE DIFFUSION IN A CHAOTIC SYSTEM - CAPILLARY WAVES IN THE FARADAY EXPERIMENT, Chaos, solitons and fractals, 5(8), 1995, pp. 1455-1464
We present experimental results for the motion of particles moving on
capillary ripples. The ripples are formed on the surface of a fluid un
dergoing vertical oscillations. We find an anomalous relative diffusio
n: particles initially close separate in time, moving more rapidly apa
rt as their distance increases. This result is surprising, as self-dif
fusion measurements indicate that single particles essentially move li
ke random walkers.