Influence of electric conductivity and pH on propagation of impulse breakdown on the surface of artificial acid rain

Recently, acid rain has become a grave environmental problem. The authors realized artificial acid rain with any electric conductivity σ and pH value by a combination of dilute sulfuric acid and seven kinds of salts based on the chemical analysis of the ionic ingredient of rainwater. In this paper, a propagation of a streamer discharge on the surface of artificial acid rain is investigated in detail by using a high‐speed Schlieren method and a current‐measuring system by LED. The results obtained may be summarized as follows:(1) A flashover voltage V f of rainwater decreases gradually with increasing the σ and an effect of the V f on the pH cannot be seen obviously in this experimental condition; (2) On the propagation of the streamer discharge on the surface of artificial acid rain.(i) In case of rain which has nearly the same pH and the different σ, the propagation length l d of streamer‐like density changes becomes larger as the σ is made larger; (ii) In case for rain which has nearly the same σ and the different pH, a remarkable difference cannot be seen in a propagation figure and a t‐l d characteristic of the streamer‐like density changes, and in a current waveform.