The Dense Plasma That Forms Inside a Sonoluminescing Bubble

date November 18, 2015
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PHYSICS DEPARTMENT COLLOQUIUM AND ACOUSTICS SEMINAR

Wednesday, November 18, 2015 4:00 p.m. in RLM 4.102

Professor Seth Putterman
Department of Physics
University of California, Los Angeles
http://acoustics-research.physics.ucla.edu/

The passage of a sound wave through a fluid with a bubble leads to pulsations that are so nonlinear that acoustic energy is concentrated by 12 orders of magnitude to make flashes of ultraviolet light as short as 35 picoseconds.  These flashes—sonoluminescence—can be seen with the unaided eye.  Time-resolved spectra reveal the formation of an ideal Planck blackbody.  The measurements are interpreted in terms of a first order phase transition to a plasma with a charge density that can exceed 1021/cc.  To study this dense plasma we have duplicated the parameter space of sonoluminescence with laser breakdown and electric discharges in dense gases.  The sparks can block broad-band high-power laser pulses and the laser breakdown can generate a plasma condensate that influences the transport properties.