Numerical simulation of the main stage of a lightning

We present a numerical model of the main stage of a lightning discharge. Within the framework of the developed model, evolution of parameters of the current channel upon the return stroke (the lightning main stage) is described by the system of equations governing conservation of mass, momentum, total energy, along with the transmission-line equations for determining the electric potential and the total current in each channel cross section. The main characteristics of lightning at the stage of the return stroke detectable experimentally, such as gas heating in the channel to temperatures in the range of 10–40 kK, the fundamental possibility of propagation of the potential-gradient wave at a speed varying from several hundredth to several tenths of the speed of light, and the possibility of the return-stroke wave propagating a relatively long distance without substantial attenuation, are demonstrated numerically. The conclusion that the developed physical and numerical model of the lightning discharge describes physical processes that occur under real conditions qualitatively correctly can be drawn based on the results on simulation of lightning discharges of various intensity.