Analysis of lightning induced electric field and its components on and above the lossy earth´s surface by modified dipole technique

In this paper, a conceptually simple and computationally efficient technique is used to analyze lightning induced electric field and its components on and above the finitely conductive earth´s surface. The present approach overcomes the limitations of Sommerfeld integral and wave-tilt function methods used for investigating the effect of earth´s conductivity on the lightning induced electric fields. The key step in the present approach is to determine the image dipole considering the effect of earth´s finite conductivity and to use the model for analyzing lightning induced electric field and its components. It has been observed that the horizontal electric field is highly affected by the earth´s conductivity; but the vertical electric field is found to be unaffected. Initially the induction component of vertical electric field is negative and changes its polarity from negative to positive, where the induction component of horizontal electric field is found to become zero, with further increase in time.