A New Type of Electrohydrodynamic Instability in Nematic Liquid Crystals with Positive Dielectric Anisotropy. I. The Existence of the Charge Injection and the Diffusion Current

An electrohydrodynamic instability in homeotropically aligned nematic samples with positive dielectric anisotropy is presented. The analogy between the present instability and the thermally induced instabilities is found in experiments. It is pointed out that the effects of the charge injection due to the thermionic omission process and of the diffusion current must be taken into account to explain the presently observed new domains.