Electrical atomization of water dripping from melting ice pieces and its possible role in thunderstorms

Abstract

When a small isolated ice piece of conical shape is suspended with its apex facing down between two horizontal parallel electrodes and an electric field of 1 to 1.6 kV cm^-1 is applied between them with the lower electrode at negative potential, a mist of fine monodisperse particles is observed for a fraction of a second from the apex of the ice piece. Charges on different ice pieces have been measured to be in the range of 10^-9-10^-8 C after the occurrence of smoke. The phenomenon has been simulated for some conditions that exist in melting layers of thunderstorms and it is proposed that ice graupel or hailstones falling in melting layers of electrified thunderstorms may produce the type of mist observed in our experiments. It is further suggested that the positively charged mist particles generated in this phenomenon may influence the cloud microphysics and might be responsible for the lower positive charge pockets sometimes reported in the bases of well-developed thunderstorms.