Question:  Can anyone provide general information about SONOLUMINESCENCE.
I read about it recently, and wonder if any practical applications
have been devised.
Obiwan

Answer:  Concerning practical applications, there is apparently a patent
several years old for doing fusion with the same kind of
stimulated bubble mechanism found in sonoluminescence - it is
actually a pretty exciting field right now.
The experimental system involved is some fluid (water will do,
in fact) in which you can induce little bubbles, and basically
speakers in the fluid to set up large amplitude standing
sound waves.  What happens is that the bubbles grow and
shrink in sync with the sound waves, and the amplitude of
that bubble oscillation is actually quite enormous - radius
changes of around a factor of 100 and volume changes of
a factor of 10^6 have been observed in single bubbles.
And just in the last few years, people have observed light
emission from these bubbles.  It apparently happens just as
the bubble is hitting its minimum radius - the great
compression that happens causes some kind of conversion of
the sound energy into extreme heating (thousands of
degrees, at least) with the result being emission of visible
light (they think some of them may even be emitting
ultraviolet light, which gets absorbed by the water).
I can give you the e-mail address of some people doing research on
this if you are interested!
Arthur Smith
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