Posted on 01/25/2006 4:13:33 AM PST by saganite
A technique that some scientists claim generates thermonuclear fusion in a benchtop apparatus works even without its controversial neutron trigger. So say the researchers who, since 2002, have reported that nuclear-fusion reactions can occur in a vat of chilled solvent agitated by ultrasound (SN: 3/6/04, p. 149: Available to subscribers at http://www.sciencenews.org/articles/20040306/fob5.asp). If this method of sparking fusion proves to be valid—a big if, critics insist—it could lead to a remarkably simple, cheap, inexhaustible power source.
Fusion reactions take place in the vat because clusters of bubbles form and then violently collapse, explains nuclear engineer and team leader Rusi P. Taleyarkhan of Purdue University in West Lafayette, Ind. A neutron or another energetic particle triggers a bubble to form in a low-pressure trough of the ultrasound waves, he says. Then, high pressure from the wave crushes the orb to an enormous density and temperature that fuse some atomic nuclei of the bubble's gas.
Taleyarkhan and his colleagues have measured neutron emissions as a sign of fusion reactions. Because the group had used neutron pulses to trigger the process, other researchers have been skeptical of its neutron readings.
In an upcoming Physical Review Letters, Taleyarkhan's team presents evidence of fusion in bubbles initiated by a uranium-based trigger that emits alpha particles instead of neutrons. "We got away from the idea of using neutrons to produce neutrons," Taleyarkhan notes.
Nonetheless, the findings still face intense skepticism. Criticisms range from doubts about experimental procedures to quarrels with interpretations of the data. "I simply do not find the results significant and/or believable," comments physicist Dan Shapira of Oak Ridge (Tenn.) National Laboratory.
Critics note that Taleyarkhan's team admits in its report that its experimental outcomes vary greatly, many of them producing no evidence of fusion. Yet to D. Felipe Gaitan of Impulse Devices in Grass Valley, Calif., the uneven outcomes are encouraging. They "could explain our inability, and that of other researchers so far, to replicate [Taleyarkhan's] results consistently," says Gaitan. Impulse Devices plans to commercialize bubble fusion.
Lawrence A. Crum of the University of Washington in Seattle says that the new work "increases the credibility" of bubble fusion. But "unless it's reproduced in someone else's lab, I'm not going to believe it," he adds.
Taleyarkhan claims that his team's findings were independently verified last year by other Purdue researchers, whom he guided. Other physicists are unconvinced.
A welcome consequence of the latest results, Crum adds, is that other researchers should find the uranium-based triggering method easier to reproduce than the neutron one. So, he says, the new work "is an important step toward determining if the results of Rusi's experiments are true."
Good luck to them.
This is really a continuation of the cold fusion debate although this experiment isn't similar to the original. Even if this phenomenon isn't fusion it's still very interesting.
Mr. Fusion.
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Now, if fusion really occurred, wouldn't there be an enormous crater, and maybe a smoking radius of obsidian, as evidence?
Or is this the 'user friendly' kind of fusion?
..trying to gen up funds.....
I don't think so. This guy Taleyharkin has been experimenting with this for years so the funds are already there. He's staked his reputation on these experiments but so far his critics have poked huge holes in his methods. This latest experiment is trying to eliminate some of the variables.
I hope it works. Nuke is our big hope to save us from oil woes.
OK, neutrons are a good sign, have they determined the energy level of the neutrons (and of course allowing for the fact that they will slow down after travelling through some mass).
Stil skeptical, but might believe it when presented with some numbers (keV, MeV level of detected particles) and reproduceable results.
cold fusion is baaack.
So much for the claim that science is uniformly, dispassionately based on fact, as oppposed to the "emotion-based" claims of religion. ;-)
Look for this quote on a crevo thread soon?
Full Disclosure: Can you say "polywater" ? Cheers!
Science is based on fact. Scepticism is very much a part of scientific inquiry and what this scientist is expressing is scepticism these results are accurate. Along with the calls by others in the article demanding the results be reproduced in other labs the scientific process is working perfectly here.
They are talking about a much more diluted brand of fusion than you are talking about. Instead of millions or billions of atoms changing from hydrogen to helium in a massive explosion, only a few do at a time, and the result is that not nearly as much energy is released at one time as there is, for example, in a hydrogen bomb.
It's a nice idea, if it works, but getting there is a serious problem. And it doesn't become "science" unless someone can replicate the results.
I suspect that he's not going to convince some people unless and until he can do something practical with it, namely produce usuable energy. If he could produce usable energy, on a net energy basis, it would be kind of hard to say that it was an illusion. Energy doesn't just appear out of nowhere.
I don't believe he needs to prove it can do anything useful although that would be great. As a scientist he's not necessarily interested in the end product. He's more interested in seeing if there's a new undiscovered nuclear process here. That alone would rewrite the science books and probably win him a Nobel.
If this is achieved(cold fusion), life as we know it will change dramatically......Kind of like when oil was discovered.
Well, that may be true, but I'm just saying that proving it with experiments that are so subtle that you've got to rely on statistical measurements is not going to convince a lot of scientists. If he produces large amounts of usable energy, that's kind of hard to argue against.
On the other hand, there are plenty of bizarro conclusions that scientists have drawn from statistical studies in other contexts. A good example is quantum entanglement. And that is largely accepted by the scientific community, so it might be possible for him to gain acceptance of the theory without producing usable energy if others can duplicate it.
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