Thermally induced hydrodynamic fluctuations below the onset of electroconvection

Abstract

Measurements of the correlation function below the electrohydrodynamic instability in a thin layer of a nematic liquid crystal reveal fluctuating convection patches. Their amplitude A\ifmmode\bar\else\textasciimacron\fi{}, correlation length \ensuremath{\xi}, and correlation time \ensuremath{\tau} can be desribed by a stochastic mean-field model. The amplitude agrees with the expected fluctuations due to thermal noise.