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Phase transition to an opaque plasma in a sonoluminescing bubble
Brian Kappus1, Shahzad Khalid, Avik Chakravarty
1Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA. kappus@physics.ucla.edu
Physical Review Letters
|July 21, 2011
Summary
Sonoluminescing xenon bubbles transition to an opaque blackbody, challenging existing models. A new phase of matter with high ionization explains this phenomenon and the bubble
Area of Science:
- Physics
- Chemistry
- Materials Science
Background:
- Sonoluminescence (SL) involves light emission from collapsing bubbles in liquids.
- Previous studies observed SL emission spectra resembling Planck blackbody radiation.
- The opacity of SL bubbles at high temperatures and densities remained unexplained by standard models.
Purpose of the Study:
- To investigate the physical mechanisms behind the opacity of sonoluminescing xenon bubbles.
- To reconcile experimental observations with theoretical models of bubble collapse.
- To explore the potential for new states of matter under extreme conditions.
Main Methods:
- Time-resolved spectrum measurements of sonoluminescing xenon bubbles.
- Development of a theoretical model incorporating reduced ionization potential.
- Analysis of line emission from excited xenon (Xe*).
Main Results:
- Observed a transition from transparency to opaque Planck blackbody radiation in xenon SL bubbles.
- Identified a discrepancy between bubble opacity and photon scattering length at high temperatures.
- Proposed a model of a new, highly ionized phase of matter within the bubble.
- Found evidence of phase segregation during the first-order transition.
Conclusions:
- Sonoluminescence originates from a novel, highly ionized phase of matter within collapsing bubbles.
- The observed opacity is explained by this new phase, resolving previous discrepancies.
- The findings suggest a first-order phase transition occurs inside sonoluminescing bubbles.
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