3-DIMENSIONAL ELECTROMAGNETIC-FIELD DUE TO ELECTRIC-DISCHARGE BY AN ANALYTICAL APPROACH

The analytical expression of the time behaviour of the current density due to an electric discharge on a three dimensional conducting slab h as been obtained by means of an analytical method. The electric discha rge is modeled by a current pulse injected in the slab. The current in jection point can be arbitrarily positioned on the surface of the slab . The diffusion equation was solved in the s domain using the techniqu e of the separation of variables. The time behaviour of the current de nsity was determined applying the inverse Laplace transform to the sol ution. The analytical results were compared with results obtained with two numerical methods, the first based on an equivalent network formu lation and the second based on a Finite Difference Time Domain method. The electromagnetic field in space has been simply determined from th e knowledge of the current density distribution.