Two-dimensional diffusion in a self-heated dusty plasma

We investigate self diffusion in a dusty plasma using the Dusty Ohio Northern University experimenT (DONUT). A two-dimensional liquid of about 100 dust particles is formed at the center of, and heated by, a toroidal gas of dust particles confined in the surrounding annular potential well. The motions of individual dust particles are recorded, allowing particle trajectories to be directly observed. The mean-squared displacement is found to increase linearly with time, in agreement with diffusion theory. Dependence of the diffusion coefficients and probability distribution functions on temperature will be presented.