Prebreakdown current pulses in DC stressed tetraester

A point-plane electrode assembly was used to apply negative and positive DC voltages to tetraester. The resulting prebreakdown currents, which appeared as bursts of generally triangular pulses with associated average charge values in the order of the picocoulomb, were observed with a wide-bandwidth digitizing oscilloscope. Two pulse regimes were identified: one in the kilohertz frequency region and the other in the megahertz region. Single- and double-pulse regimes of varying amplitudes and temporal dispositions were also recorded. Analysis of the results suggests that these pulses resulted from a current injection process followed by the simultaneous occurrence of electronic multiplication processes in the liquid phase and microdischarges within expanding low-density regions in the volume of the liquid. Complementary processes which enhanced the occurrence of these phenomena are also suggested. It was also observed that the microdischarge region was similar to the Trichel regime in electronegative gases