We present observations of sonoluminescent light pulses and their timing in the bubble cycle. We find that the flash occurs before the minimum radius at a broad distribution of time intervals with means of 133±11 ns, 130±12ns, and 35±7 ns for argon, krypton and xenon, respectively. Anomalous flashes after the minimum radius have also been observed. We show that the mean flash times correlate with the liquid-to-gas phase transition time predicted by an adiabatic van der Waals model, and do not correlate with the predictions of the shockwave model. We also show that sequential flash-to-flash timing jitter can be as large as 100 ns. By referring to models of bubble dynamics, we calibrate our laser scattering data and find that the motion of the bubble wall prior to and during SL is subsonic. Our results motivate an alternative light emission model: The adiabatic cooling of the bubble creates an excited cold condensate that emits light and breaks apart when the bubble collapses. We compare the spectra of sonoluminescence to those of cold-jet rare gas cluster experiments and show that SL spectra are similar to the spectra from rare gas cluster breakup. We use this fundamental model to account for the brightness, spectrum and timing of sonoluminescence.
|Advisor:||Segre, Carlo U.|
|School:||Illinois Institute of Technology|
|School Location:||United States -- Illinois|
|Source:||DAI-B 71/04, Dissertation Abstracts International|
|Subjects:||Condensed matter physics, Acoustics|
|Keywords:||Flash timing, Gas clusters, Light pulses, Sonoluminescence|
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