Brightened single-bubble sonoluminescence by phase-adjusted high-frequency acoustic pulse.
This paper experimentally and numerically studies the effect of a high-frequency acoustic pulse on brightening single-bubble sonoluminescence (SBSL). A polyvinylidene fluoride point-focusing transducer was driven by a 700-W pulse generator to superimpose the acoustic pulse on the sonoluminescing bubble. The center frequency of the pulse was 10 MHz and the duration was 0.15 micros. The pulse was triggered every 100 cycles of the low-frequency standing wave used to make SBSL. The intensity of SBSL was measured as a function of time lag of superimposed pulse. Only the pulse that arrived at the bubble at the early growing stage could increase the brightness. This trend was confirmed with a numerical calculation based on the Rayleigh-Plesset equation. The increased brightness reached 300% of those of the classical SBSL flashes when the time lag was correctly adjusted.
Ogi
Hirotsugu
H
Graduate School of Engineering Science, Osaka University, Machikaneyama 1-3, Toyonaka, Osaka 560-8531, Japan.
Matsuda
Atsushi
A
Wada
Kayo
K
Hirao
Masahiko
M