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Sonofusion and Bubble Fusion (Excerpt from Chapter 7)

From The Rebirth of Cold Fusion Real Science, Real Hope, Real Energy
by Steven B. Krivit and Nadine Winocur, Psy.D

"Bubble Fusion" caused quite a stir in March 2002, when a team of researchers led by Rusi Taleyarkhan of the U.S. Oak Ridge National Laboratory startled the world with, essentially, a miniature form of hot fusion. Significant evidence exists that this technique is another form of inertial confinement fusion. Its formal name is acoustic inertially confined fusion.

An unusual and little-understood phenomenon associated with bubble fusion is that, during the process, ultrasonic waves used to generate the bubbles also create discharges of light through an effect that is referred to as sonoluminescence. Although scientists have known for some time that sonoluminescence can occur when ultrasound is used to create bubbles, before the Taleyarkhan work, they did not know that it might be possible to produce fusion reactions with this method.

Using a solution of acetone and deuterium, Taleyarkhan's team bombarded the cell with acoustic (ultrasonic) waves and neutron irradiation, creating a new means to spark a hot fusion fire from nanometer-sized bubbles. [9]

In spite of this, Dr. Scott Chubb perceives Sonofusion to be closer to cold fusion. Chubb is a theoretical physicist who has worked on cold fusion as a consultant for Research Systems Corporation for more than a decade, while also being employed for the last 15 years (in areas other than cold fusion) by the U.S. Naval Research Laboratory. He explained key areas of distinction between bubble fusion and sonofusion in a somewhat technical, but thorough, science lesson:

Believe it or not, more than one form of bubble fusion exists, and this has caused a degree of confusion. In particular, the bubble fusion developed at Oak Ridge involves a phenomenon referred to as acoustic cavitation, which has also been used by Roger Stringham.

In both situations, sound waves create unstable forms of bubbles that implode, with extremely high pressure and velocity. Some people also suggest the bubbles achieve high temperature; but the implosion occurs so rapidly that the concept of temperature is not well-defined.

An important source of confusion has been that, although superficially, since both the Stringham and Oak Ridge procedures involve acoustic cavitation, at least initially, people tended to refer to both sets of results interchangeably, using the term sonofusion.

In fact, Stringham and [former associate Russ] George invented the term sonofusion, in order to distinguish their work from the Fleischmann-Pons type of cold fusion. Their experiments should be referred to as sonofusion, while the Oak Ridge experiments should be referred to as bubble fusion. [10]

Stringham discussed his many years of experience working with acoustic cavitation before his work with sonofusion:

In March of 1989, when Fleischmann and Pons announced their work, I was using the cavitation bubble as a unique research tool. I also had in the laboratory heavy water and palladium foils and piezo-driven reactors. Within a day, I was able to see that the cavitation energy produced excess heat. It seemed to me that cavitation was just as viable as the electrochemical method used by Fleischmann and Pons. My first experiments were clumsy but intriguing. Particularly evident was the condition of the palladium foil after exposure to cavitating heavy water. The metal target had melted spots (greater than 1,800 degrees Celsius) and was discolored. I was hooked. [11]

Chubb further explained the difference between sonofusion and bubble fusion:

The distinguishing feature of the Stringham (sonofusion) work is that, when the bubbles implode, they strike a metal target, while in the Oak Ridge (bubble fusion) effort, the bubbles implode upon themselves. This distinction is important because, in the presence of the metal (typically palladium), as in the sonofusion (cold fusion) case, helium-4 and tritium are produced without high energy byproducts, while in the Oak Ridge experiments, where the bubbles implode on themselves, tritium and neutrons are produced, in a manner that is more reminiscent of conventional fusion. But even in the Oak Ridge situation, the reaction does not completely mimic conventional fusion. The amounts of tritium and neutrons are very different, and this has resulted in a degree of controversy.

Storms clarified another distinction between the two:

The nuclear reactions produced by the Stringham method occur within the palladium metal, while the bubble fusion generates the nuclear reactions within a plasma generated by the bubble. In the case of Stringham's method, the bubble is used only as another [of the many] methods to inject deuterium into the [palladium] metal. [12]

To summarize the configuration differences, the sonofusion acoustic cavitation experiments use ultrasonic waves as the catalyst, and the reaction occurs in the presence of a metal (palladium) and a form of water (D 2O,) similar to cold fusion. Bubble fusion experiments use ultrasonic waves and neutron bombardment as the catalyst, but the reaction occurs in the presence of acetone, a highly flammable material, and appears to be a form of hot fusion.

In terms of potential, Stringham commented:

This is a robust method of producing excess energy several times that of the input. At this point, our work and technology is at the door of being a practical device as a power-mutiplier as in a water heater device. [13]

Russian Academy of Sciences physicist Andrei Lipson notes that his team performed work with acoustic cavitation as early as 1990, though Taleyarkhan apparently failed to cite his earlier paper published in Soviet Technical Physics Letters, as well as the translation in the American Institute of Physics journal Technical Physics Letters. Lipson's team measured neutron emissions, which provided clear evidence of a nuclear reaction in these types of experiments. He said that the Oak Ridge work is a long way from commercialization: [14]

The energy produced in bubble fusion is many orders of magnitude less than that necessary to create the effect. So, even if bubble fusion really exists, it will have much longer to get to a practical application than compared with electrochemical cold fusion. [15]

Storms pointed out an unavoidable logistical problem with bubble fusion:

This kind of fusion has been worked on at many laboratories, including Los Alamos. However, only Oak Ridge solved the critical problem of achieving sufficient temperature in the bubble. Unfortunately, the fusion rate is trivial. If they produced one watt of thermal power, the neutron flux would quickly destroy the acetone. So you see, this is not a practical method to produce fusion power. [16]