Simulation of space charge behavior in LDPE with a modified of bipolar charge transport model

In this paper, an simply ion charge transport model is proposed, compared with bipolar charge transport model. It consists of ion generation by field assisted dissociation of impurities, transport, trapping and recombination in polymer. To simplify the model, it is assumed that only one type of impurity existing in polymer. Space charge behavior is simulated with the modified model. Compared with the experiment and simulation results, space charge behavior simulated with bipolar charge transport model could not fit the experiment to some extent. It may be associated with the limitation of charge source. Introduction of ion charge in bipolar charge transport model could simulate the heterocharge accumulation near electrodes, in accordance with experiment result. It is consider that ion transport may be the dominant mechanism for the heterocharge accumulation.