The physical model for PD in tree channel and its effects on tree growth

A mathematical model for PD propagation in a single channel is put forward to illustrate the behavior of PD in tree growth. In a long channel, PD is induced by the high field near the needle tip, then propagates along the channel by field enhancement due to injected charge by PD, and stops propagating when the field becomes less than a certain value due to field divergence. By considering that tree growth is closely related to the probability distribution for PD propagation, various characteristic of tree growth can be explained in term of gas pressure and charge injection. This model also explains the fractal nature of treeing breakdown