Comment on ``Sonoluminescence as Quantum Vacuum Radiation''

The widening phenomenology of Single Bubble Sonoluminescence (SBSL) is shown to be in good agreement with a new approach to condensed matter, based on the QED coherent interactions. Some remarkable properties of SBSL are shown to emerge from the electromagnetic release of part of the latent heat of the water's vapour-liquid phase transition occurring at the bubble surface after it becomes supersonic.

This paper discusses a collective quantum effect which might play an important role in sonoluminescence experiments. We suggest that it occurs during the final stages of the collapse phase and enhances the heating of the particles inside the bubble.

A key parameter underlying the existence of sonoluminescence (SL)is the time relative to SL at which acoustic energy is radiated from the collapsed bubble. Light scattering is one route to this quantity. We disagree with the statement of Gompf and Pecha that -highly compressed water causes the minimum in scattered light to occur 700ps before SL- and that this effect leads to an overestimate of the bubble wall velocity. We discuss potential artifacts in their experimental arra...

Based on the experimental data from Weninger, Putterman & Barber, Phys. Rev. (E), 54, R2205 (1996), we offer an alternative interpretation of their experimetal results. A model of sonoluminescing bubble which proposes that the electromagnetic radiation originates from two sources: the isotropic black body or bramsstrahlung emitting core and dipole radiation-emitting shell of accelerated electrons driven by the liquid-bubble interface is outlined.

We draw attention to the fact that the popular but unproven hypothesis of shock-driven sonoluminescence is incompatible with the reported synchronicity of the single bubble sonoluminescence (SBSL) phenomenon. Moreover, it is not a necessary requirement, since we show that the sub-shock dynamic heating in gas bubble cavitation can lead to conditions required to generate intense 100ps light pulses. To wit we study the dynamics of the interior of a cavitating gas bubble subject ...

We measured the timing of sonoluminescence by observing laser light scattered from a single sonoluminescing bubble. We performed this measurement on 23.5 kHz, 17.8 kHz, 13.28 kHz and 7920 Hz systems, and found that the flash typically occurs 100 nanoseconds before the minimum radius. These results motivate a new model of sonoluminescence: the flash results from the discharge of an excited cold condensate formed during the adiabatic expansion of the bubble.

Sonoluminescence is a phenomenon which is known for some time, relatively easy to produce but still not fully understood. A milestone was discovery of procedure for creating Single Bubble Sonoluminescene (SBSL) \cite{gaitan} in 1989. Sonoluminescence in single bubble at well defined conditions, periodically produced for a long time, is well suited for a systematic study. This procedure for SBSL was for many years considered as standard one for a study this interesting phenome...

Since the first experimental results were published in the 1990s, it has been believed that the sonoluminescence flash always occurs no more than a few nanoseconds before the minimum radius of a collapsing bubble. A concurrent belief has been that the period between sonoluminescence flashes is steady on the order of a few nanoseconds, and that sonoluminescence flashes occur with a "clock-like" regularity. To the contrary, data presented here show that the sonoluminescence fla...

Several years ago Schwinger proposed a physical mechanism for sonoluminescence in terms of changes in the properties of the quantum-electrodynamic (QED) vacuum state. This mechanism is most often phrased in terms of changes in the Casimir Energy: changes in the distribution of zero-point energies and has recently been the subject of considerable controversy. The present paper further develops this quantum-vacuum approach to sonoluminescence: We calculate Bogolubov coefficient...

Single bubble sonoluminescence is understood in terms of a shock focusing towards the bubble center. We present a mechanism for significantly enhancing the effect of shock focusing, arising from the storage of energy in the acoustic modes of the gas. The modes with strongest coupling are not spherically symmetric. The storage of acoustic energy gives a framework for understanding how light intensities depend so strongly on ambient gases and liquids and suggests that the light...