ABSTRACT
This chapter covers the areas of electrical structure, charging mechanisms, and numerical models of the electrical development of thunderstorms. Thunderstorms have been of interest and concern for centuries, so it is perhaps surprising that the processes leading to thunderstorm electrification are under active debate. For the electric field to develop in storms, charges of opposite sign must be separated, and this may be caused by gravitational forces acting on oppositely charged particles of different size and aerodynamic drag or by convection currents that transport regions of charge throughout the cloud. A proposal for a thunderstorm charging mechanism was made by C. T. R. Wilson, who pointed out that cloud and precipitation particles carry polarization charges induced by the vertical fair weather electric field. Confirmation that the lower charge center is usually negative came from studies of lightning by Wilson, who identified a vertical dipole within thunderstorms, the upper charge center being positive.
