An Integral-Equation Based Leader-Return Stroke Coupled Model for Return Stroke Current and Light Simulations

Abstract:

A lightning return stroke is always preceded by a downward leader process. Consequently, the property of a downward leader takes a dominant role in determining the property of the return stroke following the leader. Besides, the channel parameters of a return stroke are all spatial and temporal variables. But these two points are ignored or scorned in most of existing return stroke models. To make up this research gap, we have developed a leader-return stroke coupled model based on the time domain electric field integral equation (TD-EFIE). With a presumed leader channel and boundary condition, a set of equations controlling the evolutions of return stroke parameters, such as the channel current, channel charge deposit, channel radius and conductance, is derived. Furthermore, based on the channel current and conductance, a set of equations for calculating the current-produced electromagnetic fields and light emissions is also derived. A trial of the present model yielded preferable results on both the return stroke current and its light emission in comparison with the observed results in literature.