Charge separation during the impact of sand on ice and its relevance to theories of thunderstorm electrification

Jayaratne, E.R., 1991. Charge separation during the impact of sand on ice and its relevance to theories of thunderstorm electrification. Atmos. Res., 26: 407-424. Grains of sand rebounding off an ice surface remove a net negative charge leaving the ice electrically positive. The magnitude of the charge separated increases as the temperature decreases and is also affected by the nature of the ice surface. A surface growing by vapour diffusion and/or by riming charges more strongly. The enhanced charging persists for some time after the growing process ends. The role of the sand particles in the charge separation process is compared with that of ice crystals in other laboratory studies with a view to understanding the physical mechanism of thunderstorm electrification.