The onset of electrothermal convection in nonpolar liquids on the basis of a dissociation-injection conductivity model

The onset of convection for a layer of nonpolar liquid subjected to an adverse thermal gradient and an intense electric field is examined. The electrical conductivity is determined by a physicochemical model that is based on dissociation and injection charge generation. Static instabilities and overstabilities are predicted as a function of strength of injection, C, and residual conduction, C/sub 0/. Physical and mathematical arguments show that for values of C larger (smaller) than approximately 2.8 C/sub 0/, the regime is injection dominated (conduction dominated). It is also shown that dissociation always plays a stabilizing role, unlike injection, which can have either a stabilizing or a destabilizing effect due to its indirect coupling with thermal perturbations.<>