title: Evolution of avalanche conducting states in electrorheological liquids.
abstract: Charge transport in electrorheological fluids is studied experimentally under strongly nonequilibrium conditions. By injecting an electrical current into a suspension of conducting nanoparticles we are able to initiate a process of self-organization which leads, in certain cases, to formation of a stable pattern which consists of continuous conducting chains of particles. The evolution of the dissipative state in such a system is a complex process. It starts as an avalanche process characterized by nucleation, growth, and thermal destruction of such dissipative elements as continuous conducting chains of particles as well as electroconvective vortices. A power-law distribution of avalanche sizes and durations, observed at this stage of the evolution, indicates that the system is in a self-organized critical state. A sharp transition into an avalanche-free state with a stable pattern of conducting chains is observed when the power dissipated in the fluid reaches its maximum. We propose a simple evolution model which obeys the maximum power condition and also shows a power-law distribution of the avalanche sizes.
authors.affiliation: Department of Physics, Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
authors.forename: A
authors.initials: A
authors.lastname: Bezryadin
authors.forename: R M
authors.initials: RM
authors.lastname: Westervelt
authors.forename: M
authors.initials: M
authors.lastname: Tinkham