Abstract:

By modeling the hot compressed gas in a sonoluminescing bubble as a thermally conducting plasma it is shown that the measured picosecond pulse widths are due to electron conduction and the rapidly changing opacity of the plasma at the onset of ionization. The model shows that these mechanisms are also responsible for the absence of an ``afterglow'' subsequent to the sonoluminescent flash, as the hot bubble expands and cools. The calculated spectra for sonoluminescing nitrogen and argon bubbles suggest that a sonoluminescing air bubble probably contains only argon, in agreement with a recent theoretical analysis. [This work was performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.]