Sonochamical reaction provides a promising process to generate a novel reaction field, but lack of reproducibility among different experimental apparatus has been pointed out. One of the reasons of this problem comes from ambiguity of the sound filed in the reactor cell. The present paper shows how sound filed is generated in a reactor cell by the irradiation of ultrasound and how it changes depending on experimental conditions comparing optically visualized sound fields and sonoluminescence which gives a measure of reaction field in the cell. Theoretical analysis of the propagation of ultrasound in the cell proposes a method to generate a sound field effectively in the cell. In sonochemistry, two types of reactors are used; one is a standing-wave type reactor such as utilization of ultrasonic cleaner, and the other is a progressive-wave type reactor inserting an ultrasonic transducer horn into the liquid. The differences in the effects of ultrasonic irradiation between these reactors are aisb discussed.
