In 1974 Clark and Dombrowski reported on an experimental study of the flow and disintegration of thin liquid sheets in an ionized gas atmosphere. They observed that the disintegration pattern was different from that which normally occurs in a neutral atmosphere and, by experimentally eliminating other possible causes, concluded that the effect was of electro-hydrodynamical nature, whereby the liquid sheet acquires a certain amount of charge from the ionized gas. In this paper the authors present a theoretical analysis of the charge sheath formation and estimate a lower bound for the electric field intensity at the liquid film surface. The field intensity calculated is of the same order of magnitude as that of conventional electrostatic sprayers. This provides further evidence that the disintegration process of Clark and Dombrowski is electro-hydrodynamical in nature.