Hybridization between the FDTD Method and Sommerfeld Integrals for Lightning Electromagnetic Field Calculation

In this paper we propose a new method for the calculation of the lightning electromagnetic field above a perfectly conducting ground. The proposed method is based on the analytical determination of the magnetic field values in the boundary of the meshed region. The computation of the electromagnetic field inside this region is performed using the FDTD (Finite Difference Time-Domain) method. One of the great advantages of this hybrid method is the possibility of taking the lightning channel outside the region of analysis, which will reduce the size of the matrix involved in this calculation. The comparison of results obtained using this approach with those obtained using other absorbing boundary conditions has shown a better accuracy for our approach.