Abstract:  Adopting both experimental and simulation methods, this study mainly discusses the effect of electrode shapes on the metal ablation under  lightning long continuing current component. In the experiment, the electrode is made of W80 material, and the test samples are aluminum 3003plates.  The ablation areas and depths of the aluminum 3003 plates are compared under the tests with three types and three curvatures electrodes. Combining the finite element electric field simulation and 2dimensional streamer development model analysis, the mechanism of the electrode’s impact on the metal ablation property is also discussed. The results show that the effect of electrode’s shape cannot be ignored in metal ablation experiments. Under the lightning long continuing current component after the last return stroke, cone electrode leads to the severest ablation both in ablation area and depth, whilst the hemisphere electrode leads to the lightest ablation. Moreover, electrode shape also affects the capability of initial ionization within the gap. The electron density and electron energy density distribution during the process of streamer development dominates the impact of electrodes on the metal ablation.

Key words:  metal, ablation characteristic, lightning current, electrode shapes, electric field simulation