Ultrasonic fusion

Original work

The story begins with the work of RP Taleyarkhan , CD West, JS Cho, RT Lahey, RI Nigmatulin , and RC Block. "Evidence for Nuclear Emissions During Acoustic Cavitation." Science 295, 1868-1873 (2002), which presents the results of an experiment on sonoluminescence in acetone , C ₃ H ₆ O, and “heavy” ( deuterated ) acetone, C ₃ D ₆ O. Sonoluminescent cavitation was initiated using an external neutron beam. When conducting experiments with heavy acetone, an increased neutron yield with an energy of 2.45 MeV (mega electron volt) was observed, as well as an increased activity of a sample of liquid with tritium (1p, 2n). Both of these signals had significant statistical significance, which allowed the authors to conclude that in the process of sonoluminescence, a thermonuclear fusion reaction of deuterium was triggered. The theoretical model of the phenomenon constructed by the authors showed the possibility of reaching a temperature of the order of millions of Kelvin during the collapse of a sonoluminescent bubble, which could well lead to a thermonuclear reaction.

Criticism of the original work

Since this work - even at the stage of reviewing - aroused great interest, there were several experimental groups ready to repeat the same measurements on the same setup in the same mode, but with their recording instruments (that is, with their scintillator and their selection system neutron events). The results of this analysis are published in D. Shapira and M. Saltmarsh, Nuclear Fusion in Collapsing Bubbles — Is It There? An Attempt to Repeat the Observation of Nuclear Emissions from Sonoluminescence , Phys. Rev. Lett. 89, 104302 (2002) and do not confirm the authors' claims. However, the authors of the original work comment on this independent experiment ( RP Taleyarkhan et al., Comment on the Shapira and Saltmarh report ), and their conclusion sounds somewhat paradoxical: on the basis of the same data, they conclude that it fully confirms their discovery.

It is also worth noting the remark made in the article by Y. Didenko and K. Suslick, Nature 418, 394 (2002), which experimentally studied chemical reactions under conditions of a sonoluminescent flash. It was noted that the numerous endothermic reactions accompanying the heating of the bubble in an organic liquid, in particular in acetone, will greatly impede the achievement of such high temperatures. Moreover, they showed that temperatures in sonoluminescence in organic liquids should be lower than in sonoluminescence in water, which runs counter to the claimed millions of Kelvin.

It was also noted that the energy of the recorded neutrons was much higher than the energy of neutrons generated during thermonuclear fusion, to which the Taleiarchan group objected that the deviation was within acceptable limits.

In March 2004, the second article of the same research group, RP Taleyarkhan et al. , Was published . Additional evidence of nuclear emissions during acoustic cavitation , Phys. Rev. E 69, 036109 (2004) (inaccessible link) , which reports the results of an improved experiment. The energy of the observed neutrons still does not correspond to the energy of the neutrons generated during the thermonuclear reaction. In contrast, B. Naranjo publishes an article where he shows that the energy spectrum of the observed neutrons corresponds to the radioactive decay of California-252 ^[1] .

In May 2005, an article by former students of Talleyarhan Yiban Xu and Adam Butt, Nuclear Engineering and Design 235, 1317 (2005) appeared , which reported the results of new experiments confirming the previously stated observation of ultrasonic fusion. However, as the authors themselves write, the experiment was carried out on the same setup and according to the same scheme as before, and without an analysis of the systematic errors of the experiment, it did not surpass the earlier experiments in accuracy. This work left unanswered critical remarks by skeptics, and therefore the scientific community received this message very cool, see the popular article Ultrasonic thermonuclear fusion: episode three on the website Elements.ru. In addition, the article became the reason for an internal investigation of Talleyarhan himself, who, according to the commission, deliberately excluded himself from the list of authors and added an author who was not involved in the work to create the appearance of an independent study.

Edward Forringer of the University of Texas, Lathornier, in November 2006, reported on the successful reproduction of Talleyarhan's observations during his experiments. It is noteworthy that he did not use an external neutron source to initiate sonoluminescence. It was shown, in particular, that the neutrons formed in the desktop reactor, which are a “marker” of the course of the thermonuclear reaction, are not related to the radioactive isotope of California used in the experiments. ^[2]

Currently, the situation is far from being resolved. Fully independent re-testing of experiments is required.

In 2006, the leadership of Purdue University, where Professor Ruzi Talleyarhan currently works, reviewed the results of Talleyarhan's work and found no signs of falsification that required further investigation.

July 18, 2008, in a special press release from Purdue University, it was reported that a special investigative committee, which included representatives of five academic institutions, made its conclusions.

Taleiarchan was accused of scientific dishonesty on two counts ^[3] . Firstly, Taleiarchan included in the co-authors the work of an employee who made an insufficiently significant contribution to it. Secondly, the professor claimed that his work received independent confirmation, while this “confirmation” was carried out by his students. Accusations of falsification of the results were not confirmed during the investigation. For example, the distortion of the neutron spectrum caused by the placement of ice between the camera and the detector was considered a bona fide delusion, since Professor Taleiarchan might not have been aware of such an effect. The evidence obtained during the investigation suggests that the authors of the original article did not delve into the intricacies of the operation of neutron detectors, relying solely on the difference in signals between the deuterated and non-deuterated liquid.

• Cold fusion
• Sonoluminescence

• For a detailed analysis of this series of works, see the popular articles Ultrasonic Thermonuclear Fusion: A Critical Analysis and Possible Sources of Error in an Ultrasonic Thermonuclear Experiment .
• Brief notes on the “discovery” and sanctions applied to RP Taleyarkhan see Storm in a glass (inaccessible link) and The author of a fake experiment with “cold fusion” is deprived of his professorship .
• Withdrawal of charges of falsification of RP Taleyarkhan see. All charges have been dropped from the "desktop fusion"