Laser-triggered electrical breakdown in liquid dielectrics. Imaging of the process by the shadowing technique

Electric breakdown in transformer oil subjected to a quasi-uniform dc electric field has been triggered by a focused laser pulse and prebreakdown discharge phenomena were imaged by the shadowing technique. Extensive data were recorded of the prebreakdown phenomena, such as streamers and gas bubble growth, from the initiation of the laser plasma to the disruptive discharge. The data was used to qualitatively and semi-quantitatively describe these phenomena. The image material also was used to improve and modify the qualitative description of the laser-triggered breakdown process previously presented by Sunesson et al. [1994].