Analysis of pressure-wave methods for the non-destructive determination of spatial charge or field distributions in homogeneous dielectrics

Detailed knowledge of the electric charge or field distribution in the bulk of dielectrics is necessary for the understanding of charge-storage and charge-transport phenomena. The most successful techniques for the experimental determination of spatial charge or field distributions in dielectrics, are based on the transit of a compression wave through the sample [1-6]. In the present study, the basic equations for pressure-pulse and pressure-step experiments are derived from first principles. The pressure dependence of the relative permittivity ε is investigated, and the influence of this dependence on the signal amplitude is calculated for nonpolar and for polar dielectrics. The response equations for pressure-step, pressure-pulse and arbitrary pressure-profile experiments are calculated.