I observed the following phenomenon in an experiment (I'm not a student of physics, just an amateur) and was hoping for an explanation.
A metal pan is electrically grounded and a layer of insulating fluid (vegetable oil) is placed in the pan. If you like, assume the pan is infinite in diameter. An electrode (a needle) is placed above the pan, pointing downward at the oil. A high voltage (-12kV) is applied to the electrode. The electrode is close enough to the pan to generate an ion wind, but not close enough to overcome the breakdown voltage of the air and oil, so there is no arc. The oil is repelled from the electrode (perhaps because it acquires a negative charge from the ion wind) and also, more remarkably, the surface of the oil begins to undulate.
My theory to explain the undulation is that the negatively charged oil on the surface is repelled from the electrode until it touches the pan, where it loses its charge and therefore is permitted to rise to the surface again, and the process repeats. So the undulations are something like convection cells, only with electric charge instead of heat.
Is this explanation correct? Is there a name for this phenomenon? Would a similar phenomenon create leakage current in capacitors with liquid dielectrics?