The surface physics of ice in thunderstorms

Laboratory and field studies have shown that thunderstorm electrification is principally due to rebounding collisions between ice particles and hail. Recent studies have provided clues for an understanding of the microphysics of the charging mechanism, involving the dynamics of vapor growth, molecular diffusion, and collisionally modified surface melting. The theory is in quantitative agreement with the systematic dependence of charge and mass transfer on growth rate, collision speed, and temperature.