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Physical Society Colloquium
Professor David Cheeke
Department of Physics In 1990 Gaitan and Crum reported results of a pioneering experiment in which a single air bubble was trapped in a remarkably stable position by an acoustic standing wave. The bubble oscillates reversibly with the sound field, and at each collapse phase of the cycle emits a tiny burst of light known as SBSL. Further work by Putterman et al showed that the effect was characterised by precise synchronicity with the sound field, extremely sharp pulses and a continuous emission spectrum in the visible. The subject has generated a lot of excitement, mainly due to indications of extremely high temperatures at the bubble centre at the minimum point of collapse.
Friday, February 12th 1999, 15:30 |