Nuclear Fusion in Collapsing Bubbles—Is It There? An Attempt to Repeat the Observation of Nuclear Emissions from Sonoluminescence

Shapira, D.; Saltmarsh, M.J.

doi:10.1103/physrevlett.89.104302

Cited by 61 publications

(44 citation statements)

References 7 publications

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“…These reports were met with immediate skepticism, and serious issues with the validity of the claims arose 14,15 . Indeed, subsequent studies in several independent laboratories have not succeeded in reproducing the original report [16][17][18] . Despite the controversy surrounding sonofusion, there is no dispute that an imploding bubble can generate high temperatures and pressures.…”

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confidence: 98%

Inertially confined plasma in an imploding bubble

2010

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Models of spherical supersonic bubble implosion in cavitating liquids predict that it could generate temperatures and densities sufficient to drive thermonuclear fusion 1,2 . Convincing evidence for fusion is yet to be shown, but the transient conditions generated by acoustic cavitation are certainly extreme 3-5 . There is, however, a remarkable lack of observable data on the conditions created during bubble collapse. Only recently has strong evidence of plasma formation been obtained 6 . Here we determine the plasma electron density, ion-broadening parameter and degree of ionization during single-bubble sonoluminescence as a function of acoustic driving pressure. We find that the electron density can be controlled over four orders of magnitude and exceed 10 21 cm −3 -comparable to the densities produced in laser-driven fusion experiments 7 -with effective plasma temperatures ranging from 7,000 to more than 16,000 K. At the highest acoustic driving force, we find that neutral Ar emission lines no longer provide an accurate measure of the conditions in the plasma. By accounting for the temporal profile of the sonoluminescence pulse and the potential optical opacity of the plasma, our results suggest that the ultimate conditions generated inside a collapsing bubble may far exceed those determined from emission from the transparent outer region of the light-emitting volume.A bubble acoustically driven into nonlinear radial oscillation can focus the diffuse energy of the sound field by many orders of magnitude 8 . The energy focusing is such that broadband light emission is observed (sonoluminescence) 4 and molecular bonds are broken (sonochemistry) 9 . Measurement of the bubble dynamics of a single sonoluminescing bubble (single-bubble sonoluminescence (SBSL)) has shown the implosion velocity to be greater than the speed of sound with enormous acceleration near maximum collapse 10 . The bubble dynamics and the properties of the emitted light suggest the generation of extreme intracavity conditions. Indeed, recent molecular dynamics simulations predict temperatures approaching 10 8 K but lasting for only a few hundred femtoseconds 2 . The extreme conditions generated during SBSL arise from quasi-adiabatic compression of the bubble contents. One measure of the intensity of bubble implosion is the ratio of maximum to minimum bubble volume (that is, compression ratio). The value of the compression ratio, and hence the bubble kinetic energy, increases with increasing acoustic pressure (P a ; ref. 11). Thus, at high P a there is more energy available to be transferred to the bubble contents, which should ultimately produce more extreme intracavity conditions.Recently, Taleyarkhan and co-workers claimed to observe neutrons during acoustic cavitation in deuterated acetone 12,13 resulting from intracavity fusion reactions (that is, 'sonofusion'). These reports were met with immediate skepticism, and serious issues with the validity of the claims arose 14,15 . Indeed, subsequent studies in several independent laboratories ha...

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confidence: 98%

Inertially confined plasma in an imploding bubble

2010

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“…Subsequent work 12 seemed to disprove the Oak Ridge experimental result. But that is not the point here.…”

Section: Not So Good: Optimization Of Enthusiasm/misjudgmentmentioning

confidence: 99%

Excellence in computer simulation

Kadanoff

2004

Comput. Sci. Eng.

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“…One of the major criticisms of these experiments [1,14] has been the use of a pulsed neutron generator to induce the production of large radius cavitation bubbles. When using a neutron generator in this mode, 10 4 neutrons are produced at the same time.…”

Section: Proposed Experimentsmentioning

confidence: 99%

Quantum Many-Body Theory of Low Energy Nuclear Reaction Induced by Acoustic Cavitation in Deuterated Liquid

Kim

Koltick

Zubarev

2005

Condensed Matter Nuclear Science

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There have been a number of reports of observation of nuclear fusion events in acoustic cavitation experiments with deuterated liquid. Some of the reported results have been interpreted as a result of achieving thermonuclear fusion temperatures (~a few keV) during acoustic bubble cavitation (ABC). We propose an alternative theoretical model for the ABC fusion based on Bose-Einstein condensation (BEC) mechanism.Our theoretical model yields two main predictions. The first prediction is that the Coulomb interaction between two charged bosons is suppressed for the case in which number N of charged bosons is large, and hence the conventional Gamow factor is absent. The second prediction is that the fusion rate depends on the probability of the BEC ground state occupation instead of the conventional Gamow factor. This implies that the fusion rate will increase as the temperature of the system is lowered since the probability of the BEC state is larger at lower temperatures. These predictions imply that the ABC fusion may be achievable at lower temperatures.A number of key improvement to acoustic cavitation experiments are proposed to check these predictions as well as the results of other experiments.

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Nuclear Fusion in Collapsing Bubbles—Is It There? An Attempt to Repeat the Observation of Nuclear Emissions from Sonoluminescence

Cited by 61 publications

References 7 publications

Inertially confined plasma in an imploding bubble

Inertially confined plasma in an imploding bubble

Excellence in computer simulation

Quantum Many-Body Theory of Low Energy Nuclear Reaction Induced by Acoustic Cavitation in Deuterated Liquid

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