Experimental measurement of the acousto-electric interaction signal in saline solution

Acoustic pressure alters local electrical conductivity in tissues and solutions. This work concerns the measurement of electrical conductivity in a liquid which is subjected to an acoustic pressure field created by a focused transducer. Measurements were made with four electrodes positioned in the ultrasonic focal zone, and the signal concerned is referred to as the acousto-electric interaction signal. A solution of sodium chloride in a measurement cell was subjected to ultrasound pressures of upto 1 MPa. It was shown that it is possible to quantitate the acousto-electric interaction signal once the ultrasonic vibration potential due to the Debye effect has been subtracted. The acousto-electric interaction signal was shown to be directly proportional to both the applied acoustic pressure and current. For the measurement cell used in this work, the interaction factor was found to be 5.3 microVmA(-1) MPa(-1).