Acoustic and optical methods for measuring electric charge distributions in dielectrics

Much progress had been made during the last two decades of acoustic and optical methods for measuring charge distributions in dielectrics. A review on this topic is given, which covers mainly the past research activities associated with that at our laboratory. For acoustic methods, we will discuss and compare the PEA and PWP methods and present some of the results that enabled us to gain some physical insights into the charge dynamics within solid plate samples and coaxial cables. For optical methods, we will discuss the Pockels effect technique that is used for the dynamic measurement of surface charge distributions, and the Kerr effect technique that is developed for measuring electric field distributions within liquid dielectrics