Correlations and Freezing in Steadily Settling Suspensions
  We study the liquid-solid transition in a collection of interacting particles moving through a dissipative medium under the action of a constant, spatially uniform external force, e.g. a charge-stabilized suspension in a fluidized bed or a flux-point lattice moving through a thin, current-carrying slab of type II superconductor. The mobility of a given region in these systems is in general a function of the local concentration. We show that the structure factor peak is suppressed in an anisotropic manner as a result of this effect, resulting in a shift of the crystal-liquid phase boundary towards the crystal side. A nonequilibrium phase diagram is presented. 
Rangan Lahiri (deceased) (TIFR, Mumbai, India) and Sriram Ramaswamy   (IISc, Bangalore, India.)