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Convection-roll instability in spite of a large stabilizing torque

Pramoda Kumar, Jana Heuer, Tibor Tóth-Katona, Nándor Éber, and Ágnes Buka
Phys. Rev. E 81, 020702(R) – Published 25 February 2010

Abstract

Two electroconvection (EC) pattern morphologies—a cellular and a subsequent roll pattern—have been detected in the same frequency range in a nematic with positive permittivity and conductivity anisotropies. The frequency dependences of the onset voltages and critical wave numbers have been determined both for homeotropic and planar alignments. It has been proven that both pattern morphologies have a dielectric time symmetry. We also discuss possible sources for the pattern formation in the frame of both the isotropic (Felici-Benard) mechanism, as well as the standard model of EC.

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  • Received 2 September 2009

DOI:https://doi.org/10.1103/PhysRevE.81.020702

©2010 American Physical Society

Authors & Affiliations

Pramoda Kumar

  • Centre for Liquid Crystal Research, Professor U.R. Rao Road, P.B. No. 1329, Jalahalli, Bangalore 560 013, India

Jana Heuer

  • Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, D-39106 Magdeburg, Germany

Tibor Tóth-Katona*, Nándor Éber, and Ágnes Buka

  • Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary

  • *Corresponding author; katona@szfki.hu

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Issue

Vol. 81, Iss. 2 — February 2010

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