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Bubble Fusion Results Replicated by 4 Institutions
Trackster writes ""TROY, N.Y. - Physical Review E has announced the publication of an article by a team of researchers from Rensselaer Polytechnic Institute (RPI), Purdue University, Oak Ridge National Laboratory (ORNL), and the Russian Academy of Science (RAS) stating that they have replicated and extended previous experimental results that indicated the occurrence of nuclear fusion using a novel approach for plasma confinement." Here's another link in case EVWorld gets burned."
Are we allowed to get excited at the possibility of a new form of energy, or do we still have maintain an air of scepticism at this unorthodox fusion method? Also does anyone know why they used D + D fusion reaction rather than the more common D + T reaction? One of the quotes suggests that it is possible, and being more energetically favourable (from what I remember), I wonder why it wasn't used.
What the article doesn't mention is how useful this might be. It appears that they have devised a reliable way to trigger a fusion reaction, but is it feasible to use it for electrical generation, for example? I understand that the major problem with fusion reactor research is that they have always consumed more energy than they have produced, making them quite useless for actually generating energy. But since they are not inducing the reaction with high-powered electromagnets as has been done in the past, would this enable the possibility of a true fusion generator?
Is it just me, or is bubble fusion a really cool concept?
This is the kind of thing real progress comes from! Not the big nasty brute force machines we've been trying to coax a usable fusion reactor out of for decades, but a clever application of the laws of physics to get tiny pockets of fusion at much more sane average temperatures and pressures. Temperatures we can work with without having to contain them in giant magnetic toruses, temperatures we don't need petawatt lasers to generate for a fraction of a second.
I can see this development panning out, but even if it doesn't I'm still in awe of it's elegance.
"The worst tyrannies were the ones where a governance required its own logic on every embedded node." - Vernor Vinge
Desktop nuclear fission, eh? Sure the power generation is less than parity, but a portable neutron generating device could be used for so many things - medical scans, security scans, neutron vision goggles...
and of course
Shark-mounted Neutron Cannon.
It's actually the better link. Not sure why the submitter chose to relegate it to second-class status.
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
We hear, every so often, that "nuclear fusion has occurred", and nothing ever comes of it. It either can't be replicated or is impractical for power generation.
Would anyone care to enlighten me as to when we'll see anything come of this promising technology, and when people will stop pussyfooting around and just increase the scale a little bit?
The trouble with fusion reactor experiments (of the tokamak kind) is that they are tremendously expensive and lengthy to build. After the previous generation of European experiments (JET) there supposed to be something like a seven-year gap before ITER would become available. IIRC the US pulled funding on their independent fusion programme, but eventually decided to join ITER too; its pretty much the only tokamak game in town.
However, due to its cost, ITER has always been mired in politics (even the site hasn't been chosen yet - 5 years after the project was supposed to have started) and this leads to more delays and increased costs.
Plasma theorists also have to find something else to do (and alternate funding) between each round of testing; seven years is a long time and people leave the subject, retire, etc, never too return. You'd be a very brave man to pin your career hopes on ITER being built on time. This then causes manpower difficulties for the project when it finally gets into gear, which then suffers more delays and overruns, etc, as postdoc researchers are trained up.
In short; expect progress when ITER is build, but don't hold your breath.
At first I thought you said "giant magnetic trousers".
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
The Tokamac people got to break even in 97(IIRC). So something, at least came of it.
The problem I see with this bubble stuff is that they detect it by the emission of neutrons. Anything which gives out lots of neutrons is going to have many of the problems of fission - any plant big enough tobe useful will need shielding and will produce nasty waste makeing decomissioning expensive.
_O_
.|< The named which can be named is not the true named
200 Hz pulses of neutrons and tuned ultrasound create cavities and grow bubbles in deuterated acetone which grow from 60 nanometers to 6 millimeters. At this point, they implode within nanoseconds, reaching estimated temperatures of 10^7 Celcius/Kelvin and 10^9 atmospheres (sea level) and releasing energy: tritium (hence fusion), light photons (sonoluminescence), gamma rays, and more neutrons. "Because the bubbles grow to such a relatively large size before they implode, their contraction causes extreme temperatures and pressures comparable to those found in the interiors of stars." "In future versions of the experiment, the tritium produced might then be used as a fuel to drive energy-producing reactions in which it fuses with deuterium."
I think the problem is that not even the physicist really know what to do with this.
That and it is Monday morning and the trolls haven't climbed out of their caves.
"I'm not high, just stupid" --JY
From the Business Week article, it looks like they're making stronger vessels to hold the liquids at very high pressures:
"Since ordinary sonoluminescence delivers so much energy at pressures of only one or two atmospheres," he says, "you could hope that at 1,000 atmospheres, you'd be in fusion territory -- if the temperature also scaled up. But that's a really big 'if."'
I'm also surprised that this isn't on the main page of Slashdot. When reading the previous article on the discovery, there was a lot of "let's wait for confirmation" messages. Now we have it and it seems an appropriate time to get excited.
The coolest part about all of this is that it's relatively cheap, with the possibility of inexpensive and clean energy. The scary aspect that I haven't seen mentioned is that it could be an good source of neutrons used to enrich uranium and make weapons-grade material.
I'm too lazy to even try an order of magnitude estimate for this, but I wonder how much the symmetry of the collapsing bubble is distorted by the gravitational pressure gradient. A few nanoseconds isn't much time to develop distortions, but 6 mm is damn big for this sort of thing. When the bubbles collapse back to nanometer scales, any deviation from spherical symmetry will become quite apparent. The question is whether gravity is a significant contributor to such imperfections when compared to thermal fluctuations, momentum from the incident neutrons, and the like. If so, conducting the reaction in microgravity could get the system that much closer to break-even (not that I expect they'll be close anytime soon, but it's fun to think about).
Bugrit! Millenium hand and shrimp!
I do not know about Princeton but the JET Experiment reached Breakeven in 1997. Spot-on about the neutron production issues though.
Wouldn't it be funny if the sheer acreage of acetone tank required to produce a watt o power makes it less economical than covering that same area with solar panels?
Eat at Joe's.
I was at a conference of the ASA a year or so ago, and those in the know at the conference stuck around in one particular room for a particular series of talks.
First the internal review committe from Oak Ridge talked about how they couldn't find much evidence that Taleyarkhan and his group had actually produced bubble fusion -- this was pretty deadly in a scientific sense, since their OWN lab was very critical of their work. But then Taleyarkhan talked, and gave careful and convincing evidence to the contrary: His group actually HAD produced bubble fusion. It was a pretty tense afternoon, though everyone seemed to be of relatively good cheer. Fun times!
I hope Taleyarkhan and his group actually do figure a way to produce and control -- and maybe harness the energies produced -- bubble fusion; since I'm in physical acoustics, this means more jobs for me to go into!
Here's an extremely lazy way to estimate it. Assuming the bubble collapse time is 100 ns (article only says "Within nanoseconds"), the top of the bubble will fall an extra 5x10^-8 microns during collapse, using the .5*g*t^2 formula. Even if I'm off by many orders of magnitude (and I'm guessing I overestimated), this is quite insignificant compared to the .06 micron size of the bubble at its smallest.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
I work at Oak Ridge National Lab (although not in physics and I don't know these folks). A physics person I spoke to that has some inside perspective seems to think that it is legit.
However, he doesn't think there are any ideas around about how it could be applied to exctract any positive energy budget at this stage (let alone any practical ones). Unfortunately.
We can just hope that more people paying attention to it will increase the likelihood that some bright person will get some ideas in that direction.
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