Electric sonic amplitude is an electroacoustic phenomenon

Electroacoustic phenomena

Electroacoustic phenomena arise when ultrasound propagates through a fluid containing ions. The associated particle motion generates electric signals because ions have electric charge. This coupling between ultrasound and electric field is called electroacoustic phenomena. Fluid might be a simple...

 that is the reverse to colloid vibration current

Colloid vibration current

Colloid vibration current is an electroacoustic phenomenon that arises when ultrasound propagates through a fluid that contains ions and either solid particles or emulsion droplets ....

. It occurs in colloids, emulsions and other heterogeneous fluids under the influence of an oscillating electric field

Electric field

In physics, an electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding...

. This field moves particles relative to the liquid, which generates ultrasound

Ultrasound

Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...

.

Electric sonic amplitude was experimentally discovered by Oja and co-authors in early 1980s. It is also widely used for characterizing ζ-potential in dispersions and emulsions. There is review of the theory of this effect, its experimental verification, and multiple applications published by Hunter.