Comment on ``Sonoluminescence as Quantum Vacuum Radiation''

In this paper we elaborate on the idea [Lohse et al., Phys. Rev. Lett. 78, 1359-1362 (1997)] that (single) sonoluminescing air bubbles rectify argon. The reason for the rectification is that nitrogen and oxygen dissociate and their reaction products dissolve in water. We give further experimental and theoretical evidence and extend the theory to other gas mixtures. We show that in the absence of chemical reactions (e.g., for inert gas mixtures) gas accumulation in strongly ac...

In a paper recently published in Science, Taleyarkhan et al. claimed to observe fusion from acoustic cavitation and the associated phenomenon of sonoluminescence. Although, this is a worthwhile line of investigation we explain why, in our opinion, their data neither proves nor disproves this possibility.

In this article we explain sonoluminescence from ideas borrowed from superradiance. The model has no free parameters and the predicted energies of quanta agree with experiment. It also hints why noble gases play a pivotal role in the effect.

A single bubble in water is excited by a standing ultrasound wave. At high intensity the bubble starts to emit light. Together with the emitted light pulse, a shock wave is generated in the liquid at collapse time. The time-dependent velocity of the outward-travelling shock is measured with an imaging technique. The pressure in the shock and in the bubble is shown to have a lower limit of 5500 bars. Visualization of the shock and the bubble at different phases of the acoustic...

It is proposed that shock wave dynamics within the gas of a small bubble explain sonoluminescence, the emission of visible radiation. As the bubble radius oscillates, shock waves develop from spherical sound waves created inside the gas bubble. As any such shock propagates toward the center, it strengthens and, upon convergence and subsequent reflection, temperature of gas inside bubble increases dramatically in such a way that it can produce plasma. Since main radiation prod...

At the Institute in Physical-Technical Problems experiments on sonoluminescence was started by our group at the beginning of 1998. The study was focused at properties of the SBSL, and the aim was to find more optimum conditions for a search for some recently predicted rare effects in SBSL- process.

We show that strong electric fields occurring in water near the surface of collapsing gas bubbles because of the flexoelectric effect can provoke dynamic electric breakdown in a micron-size region near the bubble and consider the scenario of the SBSL. The scenario is: (i) at the last stage of incomplete collapse of the bubble the gradient of pressure in water near the bubble surface has such a value and sign that the electric field arising from the flexoelectric effect exceed...

This paper discusses a quantum optical heating mechanism which might play an important role in sonoluminescence experiments. We suggest that this mechanism occurs during the final stages of the bubble collapse phase and accompanies the thermodynamic heating due to the compression of the bubble. More concretely, it is shown that a weak but highly inhomogeneous electric field, as it occurs naturally during rapid bubble deformations, can increase the temperature of strongly conf...

In this paper we present an experimental approach that allows to deduce the important dynamical parameters of single sonoluminescing bubbles (pressure amplitude, ambient radius, radius-time curve) The technique is based on a few previously confirmed theoretical assumptions and requires the knowledge of quantities such as the amplitude of the electric excitation and the phase of the flashes in the acoustic period. These quantities are easily measurable by a digital oscilloscop...

We consider an air bubble in water under conditions of single bubble sonoluminescence (SBSL) and evaluate the emitted sound field nonperturbatively for subsonic gas-liquid interface motion. Sound emission being the dominant damping mechanism, we also implement the nonperturbative sound damping in the Rayleigh-Plesset equation for the interface motion. We evaluate numerically the sound pulse emitted during bubble collapse and compare the nonperturbative and perturbative result...