Tentative explanation of the influence of electric field on the activation energy for conduction in dielectrics

Although the electrical properties of polyethylene (PE) have been measured by many authors, there is still no comprehensive theory able to fully describe the different phenomena observed. We have shown elsewhere (1) that the applied electric field, F, and pressure reduce the activation energy, E. We also observed that the existing theories do not provide a correct description of experimental results obtained under different conditions. In fact, the best fit to experimental data over a large range of fields is an exponential decrease of E with F, despite the fact that there is no theoretical support for such an empirical relation. Before entering into the discussion of the physical significance of this relation, an attempt was made to know whether it applies also to other materials.