Self-focusing of acoustic beams in a guaiacol-glycerol solution: Concentration mechanism

The possibility of experimental observation of the self-focusing of ultrasonic beams as a result of temperature and concentration nonlinearities in a stratified guaiacol-glycerol solution with a closed stratification region has been analyzed. The estimation showed that the thermally induced ultrasound self-focusing can be observed in a frequency range from 1 to 10 MHz at ultrasonic pulse durations of 1 to 25 s and energies below 3 J. The concentration mechanism of self-focusing can be observed only in the immediate vicinity of the lower critical point of solution stratification at an average acoustic beam intensity of ∼1 Wm⁻² and a pulse duration longer than 100 s. It is shown that a medium must be exposed to a pulsed periodic sound beam to experimentally implement these conditions.