Charge saturation in splashing of large drops on solid spheres

Abstract

The charges acquired by insulated metal and ice-coated metal spheres in successive splashings with large drops of water and solution have been investigated. The accumulated charge varies with the number of splashes, quickly tending to a saturation value which depends on the nature of the solid surface, the charge of the drops, their chemical composition and the presence and magnitude of external electric fields. The impact velocity and the initial charge on the sphere have no influence on the saturation values. Saturation potentials were of the order of 10 V. Increasing fields, both positive and negative, along the relative motion sphere-drop, modify the saturation charges toward a virtually constant value. The results are interpreted and their possible importance in cloud physics is discussed.