8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Wed 711:10-14:00P5.129Clogging and jamming transitions of particles flowingthrough obstacle arraysCharles Reichhardt 1 and Cynthia Reichhardt 11 Los Alamos National Laboratory, P. O. Box 1663, 87545, Los Alamos, New Mexico,United States of AmericaWe perform numerical simulations of charged and uncharged colloidal particles moving overperiodic [1] and random [2] substrates which can be created with optical means. We first examinethe case of interacting colloids moving through a partially disordered substrate, where a variety ofdifferent types of dynamical phases can arise depending on the particle density. We specificallydemonstrate a transition to a state with clogging behavior, where clogging is defined as theheterogeneous buildup of immobile particles which begins in specific localized areas and spreadsthroughout the system. We also show that the clogged states exhibit interesting memory effects.Once the system has organized into a clogged state for one direction of driving, it becomesunclogged when a new drive is applied perpendicular to the original driving direction. This occurseven in cases where the system would have become clogged if the system had been driven only inthe perpendicular direction starting from an unclogged state.[1] A. Libal, C. J. Olson Reichhardt, B. Janko, and C. Reichhardt, Phys. Rev. Lett. 96,188301 (2006).[2] C. Reichhardt and C. J. Olson Reichhardt, Phys. Rev. E 79, 061403 (2009).129