Shock Waves from a Lightning Discharge

The analytical and numerical analysis of lightning direct effects has mainly been focused on thermoelectric effects of different lightning current components. Mechanical forces created by the electric current flow, by blasting of materials (epoxy resin, metallic protection, coatings) or by shock waves caused by a supersonic expansion of the plasma channel have rarely been taken into account so far. The present publication concentrates on lightning shock waves caused by a rapid temperature rise of the plasma channel due to resistive Joule heating. In this context it is first of all necessary to understand the underlying physical mechanisms of this effect. Furthermore, theoretical models for the interpretation of experimental tests as well as for reliable prediction of the magnitude of the shock wave pressure pulses have to be provided. Finally, the temporal and spatial propagation of the shockwaves and pressures that are needed as input for the simulation of mechanical damage prediction are derived from semi-analytical and numerical computations.