TRANSITION TO CHAOTIZATION AND LOSS OF SELF-AVERAGING IN 2-DIMENSIONAL 2-PHASE MEDIA AT THE FLOW THRESHOLD

Giant fluctuations of the electric field recently identified experimen tally in two-dimensional two-phase media at the percolation threshold are discussed. An example of a hierarchical realization of these media is used to show that for Re sigma(i)=0 (where sigma(1) and sigma(2) a re the phase conductivities) and Im sigma(2)/lm sigma(1)>0, the hierar chy construction procedure yields the Dykhne expression sigma(e) = roo t sigma(1), sigma(2,) whereas for Im sigma(2)/Im sigma(1)<0, the proce dure becomes randomized and the medium loses its property of self-aver aging. (C) 1997 American Institute of Physics. [S1063-7850(97)01607-8] .