Electrohydrodynamic instability and equilibrium shapes of two charged drops

The equilibrium shapes of two closely located charged drops of comparable size are calculated on the basis of mode analysis. It is shown that the drop shapes are largely determined by the amplitudes of the second and third capillary waves and are spheroidal or pearlike, depending on the distance between the drops and on the charge magnitude and sign. The contribution of the higher modes of capillary waves to the formation of the equilibrium drop surface relief is negligibly small. For a pair of opposite-charged drops, the critical conditions of instability with respect to the proper and induced charge superposition are determined in the form of relations between the Rayleigh parameters of the drops and distance between them.