Prebreakdown events in DC and AC stressed n-hexane

An imaging system using shadow-graph optics in conjunction with a 3-ns-duration pulse laser was used to investigate prebreakdown events in DC and AC stressed n-hexane. The use of either DC or AC was shown to produce results that are essentially identical for a given electrode polarity. In addition, the prebreakdown images obtained bear a strong resemblance to those seen in impulse tests. This result suggests that prebreakdown events respond principally to the magnitude and polarity of the applied electric field, and that space charge and liquid motion exert minor influence.<>