Star in the Jar

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Hiller, R. et al. (1994) Effect of noble gas doping in single-bubble sonoluminescence, Science 266, 248–250. A group of scientists claims to have found evidence of nuclear fusion in a vase-size flask of liquid. The researchers say they created tiny bubbles that seemed to have collapsed with enough violence to force atomic nuclei to fuse. BUBBLE MAGIC. In a flask of acetone bombarded by sound waves, a cloud of bubbles (arrow) briefly swells to the size of a pea before collapsing. Courtesy of Oak Ridge Natl. Lab., Rensselaer Polytechnic Inst., Russian Acad. Sci. THE BIG SQUASH. A neutron pulse (arrow) combines with a sound signal (blue) in a flask of acetone to generate the conditions for a bubble (brown) to form, grow, and then implode with great force. After Taleyarkhan et al./Science The basis of the new energy source would be so-called sonoluminescence–a phenomenon in which bubbles of vapor in a liquid bombarded by sound waves rapidly implode, generating heat spikes and flashes of light in the bubbles (SN: 10/6/01, p. 213: Shrimps spew bubbles as hot as the sun). Taleyarkhan and several of his Oak Ridge colleagues collaborated on the research with scientists from Rensselaer Polytechnic Institute in Troy, N.Y., and the Russian Academy of Sciences in Ufa. Under extreme pressure and at temperatures of millions of degrees, such as at the center of the sun, deuterium atoms fuse in a reaction whose products include tritium–hydrogen’s radioactive heavy isotope–and neutrons. This lays the groundwork for the exciting high-performance plasma operations expected in the near future," Gates said.

His headmaster was concerned about safety. “There was the chance that I could be electrocuted by the high-voltage power supply ... and then probably the chance of the vacuum chamber imploding because of all the forces on it,” says Edwards, “but quite a minimal aspect to it was the radiation.” Using his younger sister’s fish tank filled with a water and boron solution: “The radiation wasn’t really an issue.” He is already thinking about his next project. “I was thinking that maybe I could make a hand-held laser cutter,” says Edwards. “So I’ve been looking into some really high-powered lasers.” Barber, B. P. and Putterman, S. J. (1991) Observation of synchronous picosecond sonoluminescence, Nature 352, 318–320; The measured pulse width is less than 50ps. What causes the glow? Good question. According to [Justin], we just don’t know for sure what causes it, although the leading theory is that cavitation of the bubble causes the trapped gas to compress and heat violently, turning into a brief bit of plasma. But there are problems with that theory, which is one of the reasons he wanted to show just how easy the process can be – now that he’s shaken out the bugs with five years of effort. It wasn’t easy getting the transducers attached and the driver circuit properly tuned, but with little more than a signal generator, an audio amp, and a spool of magnet wire, you too can make your own “star in a jar.” In terms of the big-picture goal, Gates said that nuclear fusion reactors, if properly developed and deployed, would provide the planet with safe, clean and virtually inexhaustible energy.

In the new work, Taleyarkhan and his collaborators used bursts of neutrons to fabricate clouds of short-lived, but extraordinarily large, sonoluminescence bubbles in acetone, the solvent in many nail-polish removers. In some tests, the researchers filled the flask with ordinary acetone, whose molecules each contain six hydrogen atoms. In other tests, they used deuterated acetone, in which deuterium atoms replace the hydrogen ones.

However, he adds, mathematical models of the process suggest that much greater energy production may be possible. Of more immediate concern to him and his colleagues is the task of convincing other scientists that their evidence of fusion is sound. If nothing else, [Justin Atkin] is persistent. How else do you explain a five-year quest to create sonoluminescence with simple tools?We applaud [Justin]’s determination to bring this project to a successful conclusion. It’s not unlike his dogged effort to make a cold plasma torch, or even his desktop radio telescope. D. F. Gaitan, (1990) An experimental investigation of acoustic cavitation in gaseous liquids, Ph. D. thesis, Univ. of Mississippi; Gaitan, D. F. et al. (1992) Sonoluminescence and bubble dynamics for a single, stable, cavitation bubble, J. Acoust. Soc. Am. 91, 3166–3183. They just don’t have the evidence,” says William C. Moss of Lawrence Livermore (Calif.) National Laboratory, one of several sonoluminescence specialists who have theorized that fusion in collapsing bubbles is feasible. Fusion is a problem best solved by the peoples of all nations working together, since the entire world will benefit from it." Several detractors have compared the new Science report to the infamous “cold fusion” announcement made in 1989 (SN: 4/1/89, p. 196). Two electrochemists claimed then to have sparked fusion at room temperature by passing electric current through a bath of water in which ordinary hydrogen is replaced by deuterium, a heavier isotope. However, neither the original pair nor anyone else could reproduce those findings, which have since largely been discredited as a case study of mistaken science (SN: 6/22/91, p. 392).