Critical dynamics of a binary fluid mixture in a centrifugal field

Critical phenomena in a fluid mixture near the consolute point have been investigated with the use of an ultracentrifuge. This method provides an opportunity to determine both dynamical and static properties of the system. The sedimentation and diffusion coefficients have been measured and a huge sedimentation effect has been observed with the coefficient $s$ diverging as ${(T-T_c)}^{-1\mathrm{}\pm 0.1}$ while approaching the critical point. The susceptibility $\frac{\partial c}{\partial \mu }$ has been measured in a wide range of concentration variations. The results confirm scaling theory. Some nonlinear effects, including an instability of the mixture close to $T_c$, have been observed.