Electric field of surface discharge inception by electrification charge

AbstractIt is well known that a surface discharge is significantly affected by the electrification charge on the surface of an insulator. However, only limited information is available concerning the electric field strength of a surface discharge produced by the charge itself. This paper describes the relationship between the surface discharge inception field caused by the charge itself and the pressure. After electrification of the surface of a film covering a plane electrode by a corona discharge produced with a needle electrode, this electrode system was placed in a vacuum chamber and the pressure was lowered. A weak discharge momentarily occurred at a critical pressure around the center of the electrification charge. We obtained the relation between the maximum field strength and the critical pressure in the range of about 50 to 1000 hPa. It should be emphasized that the inception electric field was 6 to 8 kV/mm at atmospheric pressure and 0.5 kV/mm at 50 hPa. Finally, these results are discussed, comparing the flashover voltage of the uniform field and the electric field of discharge inception obtained by experiments at various altitudes in lightning clouds. © 2003 Wiley Perio