Onset voltages of atmospheric corona discharges on plants

In this article, experimental studies of the onset voltages and of the low current region of negative atmospheric corona discharge on trees are presented. Recent experiments show that the corona discharges on natural biological objects often differ from the classical discharges with metal electrodes. The onset voltage values lie in a wide range around the expected value. It has been found that the negative corona onset voltage of multiple point (such as the top of a coniferous tree) is higher than that of a single point. VA characteristics of multiple point coronas lie below those for a single point from the onset until a critical value is reached. From this point, the slope of the characteristics is steeper for the multipoint geometry. The effect of the multiple point configurations depends mainly on separation of needles. When the needles are closed together the case of the needles of spruce or pine - the needles behave as a single needle. The difference may be caused by the presence of complex hydrocarbons released from the plants and the changes in the surrounding atmosphere.