The effect of an alternating electric field on the liquid dielectric convection in a horizontal capacitor

The electroconvective instability in a low conducting nonuniformly heated liquid occurring in an alternating electric field between plates of a horizontal plane capacitor was studied in terms of the equations of electrohydrodynamics for arbitrary field modulation frequencies and various shapes (harmonic and triangular). In the gravitational field, the instability is determined by the interplay of dielectrophoretic and thermogravitational mechanisms. The layer heated from above can feature the parametric instability. In the low-frequency range, a numerical solution to the problem obtained by the Floquet method well agrees with the asymptotic results.