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Summary: VOLUME 76, NUMBER 2 P H Y S I C A L R E V I E W L E T T E R S 8 JANUARY 1996
Origin of Traveling Rolls in Electroconvection of Nematic Liquid Crystals
Michael Dennin,1
Martin Treiber,2
Lorenz Kramer,2
Guenter Ahlers,1
and David S. Cannell1
1
Department of Physics and Center for Nonlinear Science, University of California at Santa Barbara,
Santa Barbara, California 93106
2
Physikalisches Institut der Universität Bayreuth, D-95440 Bayreuth, Germany
(Received 3 May 1995)
Electroconvection in nematic liquid crystals exhibits a Hopf bifurcation to traveling rolls for a wide
parameter range. The model normally used to describe electroconvection fails to predict this. A recent
theoretical extension, the weak-electrolyte model, incorporates the dissociation-recombination reaction
of the ionic dopant in the sample and does predict a Hopf bifurcation for a range of parameter values.
We present a quantitative experimental test of this theory using the nematic liquid crystal I52. Measured
Hopf frequencies at the onset of convection agree well with the theory.
PACS numbers: 83.70.Jr, 47.20.Ky, 47.65.+a
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