Electrical conduction of purified cyclohexane in a divergent electric field

The electrical conduction of purified cyclohexane with point-plane electrode geometry was studied as a function of point radius ( approximately 0.1 to 10 mu m) and hydrostatic pressure (10⁴ to 5*10⁶ Pa). The parameter with the greatest influence on the observed phenomena is the radius r_p of the point. The results indicate a field emission or field ionization regime for sharp points only at r_p<0.5 mu m. For larger point radii (r_p>0.5 mu m), the results depend greatly on polarity. For negative points, above a threshold electric field of 7+or-2 MV/cm (a field much lower than that required for field emission) a highly regular pulse regime is observed. This pulse regime shows all the characteristics of the Trichel regime observed in electronegative gases with the exception of no pressure dependence. This leads to the consideration of a mechanism of corona discharge occurring in the liquid phase. For positive points of r_p>0.5 mu m the observed phenomena were poorly reproducible. Current bursts, randomly distributed, were also detected at fields at the point above 5 MV/cm but with a very low count rate.