Quasi-static analysis of lightning-radiated electric field in the vicinity of sea-land structure

• Electric field of a lightning return stroke above a sea-land structure is computed.
• A closed-form time-domain solution is presented for the radiated electric field.
• The 3D Poisson's equation in the presence of the sea-land structure is solved.
• The proposed approach is valid at near distance range from the lightning channel.

A quasi-static approach is presented to compute electric field radiated by a lightning return stroke above the sea-land structure modeled as a dielectric half space with a perfectly conducting half plane situated in its interface. It appears that the quasi-static approach provides a closed-form time-domain solution for the radiated electric field. The proposed approach is mainly based on the electrostatic solution of the structure. The governing Poisson's equation in the presence of the sea-land structure is solved in three dimensions, using the contributions of dielectric half space and perfectly conducting half plane. The solution, expressed in terms of image contributions, consists of two point images in physical space. The validity domain of the time-domain quasi-static approach is investigated by comparison of the obtained electric fields with full-wave results obtained using the finite-difference time-domain method. The proposed approach has a reasonable accuracy at near (200 m) distance range from the lightning channel.