RELATIVE PARTICLE MOTION IN CAPILLARY WAVES

When a container of fluid is oscillated vertically, capillary waves de velop on the surface if the amplitude exceeds a critical value. Experi mentally one finds that the motion of small particles on the surface o f the fluid is close to Brownian. Here we study the relative motion of particle pairs. The experiment establishes that particle motion is st rongly correlated over macroscopic distances. Our observations are in striking agreement with upper-ocean studies, and with theories that ap pear applicable to this ''weak turbulence'' problem, and in disagreeme nt with experimental and theoretical results for two-dimensional large -scale atmospheric turbulence.