DOMAINS AND VORTICAL FLOWS IN A NEMATIC PHENYL BENZOATE UNDER TRANSVERSE ELECTRIC-FIELDS

Electrohydrodynamic instabilities have been investigated for an initia lly homogeneously aligned nematic with a positive dielectric anisotrop y, employing the transverse geometry. Optical threshold corresponds to the onset of out-of-plane director deviations and is higher than the threshold derived from transient responses; the latter shows a non-lin ear increase with electrode separation. Along the flow lines, the degr ee of distortion varies continuously. These results do not seem to fol low completely from the known models of the instabilities.