Numerical analysis of packet-like charge behavior in low-density polyethylene under DC high electric field

In our previous paper, we found an interesting packet-like charge behavior in low- density polyethylene (LDPE) under high dc electric field of more than 1 MV/cm. When such a high dc electric field was applied to LDPE film, a huge amount of positive packet-like charge of more than 100 C/m³ was injected into the bulk of the film and it moved towards the cathode side increasing its amount of charge. The movement of the packet-like charge gradually became slowly, and then it stopped in the bulk as it seems to be a stable state. Consequently, the electric field near the cathode was sometimes enhanced by up to more than twice the applied electric field. To analyze the feature of the positive packet-like charge behavior in LDPE, we carry out a simple numerical simulation based on the experimental results in the previous paper. The model is considered the principle of conservation of charge and the hypothesis that there are two different conductivity in front and rear of the packet-like charge in the sample. The hypothesis is based on the idea that the zone where is passed through by the packet-like charge has a higher conductivity than that in front of the packet-like charge because the charge traps are filled by passing of the packet-like charge. By considering such a simple model, we have a good agreement between the numerical simulation and the experimental results.