the sonoluminesence

Presentation, study and practice the phenomenon of Sonoluminescence 12 pages F.Moulin.

Excerpt: study sonoluminescence


Sonoluminescence is the conversion of "sound into light". It occurs when one or more bubbles, trapped inside a liquid by a sinusoidal acoustic field, are forced to oscillate during the phases of compression and depression of the acoustic wave. The non-linear behavior of each bubble oscillator then becomes very particular. Indeed, when the amplitude of the incident sound pressure on the bubble exceeds the bar, we then observe, after an expansion phase of the bubble, a very sudden compression phase which leads to the collapse of the bubble during from which extreme pressure and temperature conditions are reached inside the bubble. Among all the interesting phenomena which are then observed, the emission of light by the bubble is certainly the most intriguing.

Despite the important advances made on this subject, the mechanism of light production as well as the estimate of the temperature reached inside this bubble are not yet fully understood and several theories attempt to explain this mechanism.

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History of Sonoluminescence

The phenomenon of sonoluminescence appears when a small gas bubble rapidly collapses in a fluid. There are two classifications of sonoluminescence: sonoluminescence emitted by multiple bubbles (Multiple Bubble SonoLuminescence, MBSL) and sonoluminescence emitted by a single bubble (Single Bubble Sonoluminescence, SBSL). In 1933, N. Marines and JJ Trillat observed that photographic plates were impressed by immersion in an ultrasonically stirred liquid, thus uncovering MBSL. In 1934, H. Frenzel and H. Scholtes of the University of Cologne wrote that they could reproducibly produce weak but visible light in water using ultrasound. It is difficult to study MBSL because the bubbles only last for a few acoustic cycles, emit light for only a few nanoseconds and are in constant motion.

These limitations halted sonoluminescence research until the successful production of SBSL, discovered in 1988 when HG Flynn wrote a compilation of theoretical models of the motion of acoustically-driven bubbles. From this information, DF Gaitan, then a doctoral student, was the first to observe and control the phenomenon of sonoluminescence with a single bubble that imploded without being destroyed about 20 times per second under the effect of a pressure wave. stationary produced by ultrasound. SBSL is much easier to study because a single bubble is stationary trapped in a tank. This bubble can be extremely stable and glow for several minutes, making it possible to study the bubble and the emitted light visible to the naked eye. It is this type of sonoluminescence that we propose to highlight and study experimentally here.

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Video of sonoluminescence visible to the naked eye

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