MODEL OF ELECTRIC CHARGES IN THUNDERSTORMS AND ASSOCIATED LIGHTNING

An axisymmetrical electrostatic model of charges in a thunderstorm clo ud at the mature stage is used to initiate a bidirectional vertical le ader that develops into either a cloud-to-ground or an intracloud flas h from the regions of maximum electric field. The principal result of this study is the determination of the physical and quantitative relat ionships among cloud charges, potentials, and electric fields, and the induced charges, currents, and electric field changes of the lightnin g channel from the numerical solution of the Poisson equation for a cl oud charge model with lightning. An important consequence of the model is that the upper part of the cloud-to-ground leader and the lower pa rt of the intracloud leader terminate inside the cloud.