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Science

Bubble Fusion Results Replicated by 4 Institutions 107

Posted by Hemos from the moving-towards-more dept.
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."
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Bubble Fusion Results Replicated by 4 Institutions More

Bubble Fusion Results Replicated by 4 Institutions

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  • Can someone tell me (Score:5, Interesting)

    by loadquo ( 659316 ) on Monday April 19, 2004 @08:10AM (#8902970) Homepage
    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.
    • I don't think we're allowed to get excited by this possibility, because it was used in a crappy movie.

    • Re:Can someone tell me (Score:5, Interesting)

      by TwistedGreen ( 80055 ) on Monday April 19, 2004 @09:34AM (#8903545)
      It's because fusion has had a bad track record in the scientific community: there have been many "snake oil" cases where devices which claimed to be based on fusion--specifically, cold fusion--were in fact complete hoaxes. That researchers are being cautious is very understandable. Notice that nobody dares mention that this is "cold" (or at least "cool") fusion.

      Also, this isn't a new form of energy. It's just a novel and promising way of tapping the energy released by fusion.

      But this certainly does not look like snake oil, and it HAS been replicated several times as the articles report. So I think it's time to get excited!

      • Re:Can someone tell me (Score:4, Insightful)

        by TheLink ( 130905 ) on Monday April 19, 2004 @12:21PM (#8905476) Journal
        Personally I think there's some interesting phenomenom in at least some of that "cold fusion" stuff (see the Wired article on it). Whether or not it is cold fusion, there's evidence that there's something interesting enough that's worth at least a few millions to be pumped in.

        The hot fusion folk have spent billions so what's a fraction of that to investigate something new and interesting?

        Sure Pons and Fleischman screwed up - but it seems like the scientific community was not very objective about it - rather emotional in fact.

        • Re:Can someone tell me (Score:4, Interesting)

          by Anonymous Coward on Monday April 19, 2004 @12:49PM (#8905937)
          Sure Pons and Fleischman screwed up - but it seems like the scientific community was not very objective about it - rather emotional in fact.
          I don't understand this statement. Consider just the facts that come immediately to my mind:
          • P&F bypassed peer review and had a hyped press conference, and then shut down their labs to investigation.
          • They then refused to release any meaningful details of their experiment.
          • Nobody could confirm their results in full (some confirmed one part, while another confirmed another).
          • When people starting questioning whether any effect existed, lawyers were brought in and threats of libel suits were aired towards anyone thinking of writing a critique in a journal or the popular press.
          Given this background, where did the scientific community come off as being not very objective?
          • Given that background? Not very objective - that background isn't even _focusing_ on the scientific stuff, more on P and F.

            If some confirmed some parts and some other parts, it doesn't prove the phenomena isn't there.

            It just indicates that it might be difficult to reproduce.

            The scientific community did the equivalent of chucking the whole thing into the trash (including related stuff). Not objective.

            Heck on the same terms I could say man-made hot fusion has been proven not to be viable - given the diffi

          • I don't understand this statement. Consider just the facts that come immediately to my mind:

            I do.


            P&F bypassed peer review and had a hyped press conference, and then shut down their labs to investigation.
            Thats a flaw of the magazine where they published.

            They then refused to release any meaningful details of their experiment.
            The released "what they did" and "what they found".


            Nobody could confirm their results in full (some confirmed one part, while another confirmed another).
            Uncorrect. t
      • Notice that nobody dares mention that this is "cold" (or at least "cool") fusion.
        From the article:
        Moving at about the speed of sound, the internal shock waves impacted at the center of the bubbles causing very high compression and accompanying temperatures of about 100 million Kelvin.
        If 100 million Kelvin is "cold" or "cool", I do not think that means what you think it means.

        • Re:Can someone tell me (Score:3, Informative)

          by dbrutus ( 71639 )
          It's cold in the sense that you don't have to have huge containment systems to avoid heat death from your sonofusion experiment. You can run this stuff on a regular lab table.
          • Right. But "cold" in the sense of "cold fusion" means explicitly that none of these high temperatures and pressures are used. In the supposed cold fusion of the '80s, it was supposed to occur through some mysterious mechanism when electrolysing heavy water with platinum electrodes. Of course it didn't actually happen and there was no reason it should.

            In this case there is a viable mechanism since the bubbles potentially can generate the high instantaneous pressure and energy that is known to be necessa


            • it was supposed to occur through some mysterious mechanism when electrolysing heavy water with platinum electrodes. Of course it didn't actually happen and there was no reason it should.

              Thats wrong.

              No one ever claimed that "electrolysing" would cause a "cold fusion".

              There are several cold fuson experimental set ups. A lot of them, e.g. myon catalized cold fusion works.

              You are reffering to the P&F approach where they thought this would happen: hydrogen (deuterium and tritium as well) get sucked up

    • Re:Can someone tell me (Score:5, Informative)

      by another_henry ( 570767 ) <slashdot AT henryhallam DOT cjb DOT net> on Monday April 19, 2004 @03:16PM (#8907723) Homepage
      D+D is easier than D+T, it requires less energy and the fusion cross-section is larger. You can get excited if you like but even if this news is correct (which would be pretty cool) power plants are many years away.

      Also, fusion is not the wonderous clean energy source it's made out to be, because any type of fusion that's realistically possible outside of a star also produces neutrons, which activate the reactor materials leading to significant amounts of radioactive waste. That said, the waste problem is not so severe as with fission plants because generally isotopes with short halflifes are produced.

      For more information about fusion in general and amateur efforts in particular - I'm building a tabletop reactor - check out http://www.fusor.net/ [fusor.net]

      • Also, fusion is not the wonderous clean energy source it's made out to be, because any type of fusion that's realistically possible outside of a star also produces neutrons, which activate the reactor materials leading to significant amounts of radioactive waste. That said, the waste problem is not so severe as with fission plants because generally isotopes with short halflifes are produced.

        Would it be possible to shield the reactor with water? IIRC, neutrons + water tends to produce deuterium and tritiu
        • Water is moderately (bad pun) effective at shielding neutrons and would probably be used anyway in order to provide steam to operate turbines. I don't see how n+H could give T, but it might produce some D. However the oxygen would no doubt get activated too and that's not much use to anyone. I think the plan, for Tokamaks at least, is to use a large blanket of lithium, and "breed" this into tritium for fuel use. In fact (not sure about this) they might use molten lithium as the working fluid instead of
      • That's the same issue as with fission - screening. There's enough expertise to the problem at this time to make small-sized, insulated fission chambers.

        And it's not so critical, either - neutron absorbtion won't activate everything undiscriminately - there are stability thresholds for isotopes and even then, all you get is a beta decay - gee, more electrons to the world(*) (unless, of course, the radiating nucleus happens to be insode your body, which can be annoying when in large quantities). You do have
      • One plus for fusion over fission is that, as it currently stands you cannot create a pure fusion bomb, so heavy water is not as dangerous as letting the world play around with Uranium and isotopes that can be generated from it.

        I am looking for something that will be able to replace depleting Oil and Gas reserves for power generation, in the developing as well as the developed world. And while pebble bed reactors look good from the non-proliferation and safety side of things, they are not so good on the re-

      • Re:Can someone tell me (Score:1, Informative)

        by Anonymous Coward
        Actually, D-T has a larger interaction cross-section by two orders of magnitude up to very high temperatures (~100 keV), so you would get a considerably higher yield for the same energy input. However, tritium is not as practical in a lab setting because:
        1) it's a beta emitter (thus more paperwork)
        2) it's more difficult to acquire

        Plus, it's easier to shield the 2.45 MeV D-D neutrons than the screaming 14.1 MeV D-T neutrons.
      • No. D+T is easier, but produces neutrons. The neutrons need to be absorbed into a Lithium blanket to breed more T. This does however also involve spraying the inner parts of the reactor structure with neutrons, producing some medium-level radioactive waste (although far less per GW year than fission.

        D+He3 produces next to no neutrons, but there is no decent source of He3.

        I was told recently that D+D can be "discouraged" from producing neutrons by doing
        something clever with magnetic fields and nuclear spin

    • Re:Can someone tell me (Score:1, Interesting)

      by Anonymous Coward
      One of their proofs that fusion occurred was the generation of tritium. They went from completely non-radioactive deuterated acetone to flashes of neutrons to a verified residue of tritum. If they had tritum already in the system the experiment would be a bit less convincing - important considering everyone's skepticism. Besides, if you can get it hot enough to fuse D-D, why not?

    • Your worried its going to be another Fleisch in the Pon ?

    • 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 di

  • Usefulness? (Score:4, Interesting)

    by TwistedGreen ( 80055 ) on Monday April 19, 2004 @08:46AM (#8903212)
    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?

    • Re:Usefulness? (Score:5, Informative)

      by AlXtreme ( 223728 ) on Monday April 19, 2004 @08:56AM (#8903281) Homepage Journal
      "We are not yet at break-even," Taleyarkhan said. "That would be the ultimate. I don't know if it will ever happen, but we are hopeful that it will and don't see any clear reason why not. In the future we will attempt to scale up this system and see how far we can go."
      From the ScienceDaily article, don't hold your breath just yet...
      • Oh, thanks, I didn't realize the ScienceDaily article was different.

      • Re:Usefulness? (Score:4, Interesting)

        by harrkev ( 623093 ) <kevin.harrelson@ ... om minus painter> on Monday April 19, 2004 @12:19PM (#8905437) Homepage
        Riiiight. Don't hold your breath.

        First, I am not a physicist, but I suspect that "break-even" is defined as the TOTAL power output of the system! The problem is that to be useful, you have to get USABLE power out of the system.

        If the energy comes out as heat, then you have to run a turbine, which is not terribly efficient. If the output energy is in the form of neutrons, then I do not know how you could get anything useful out of that other than a new and novel wey to irradiate and heat things.

        So, if a physicist says that they have reached "break-even," then they are still only halfway there!

        • Re:Usefulness? (Score:3, Insightful)

          by RML ( 135014 )
          First, I am not a physicist, but I suspect that "break-even" is defined as the TOTAL power output of the system!

          All the energy put in comes out again (as heat, light, sound, etc), plus some additional energy released by the fusion. Since the total energy output must be greater than the input, but they haven't "broken even", they must be referring to the usable energy.
          • most likely, break-even is defined as the total power GAINED from fusion is greater than the input.

            So if output = input + fusion
            then breakeven is implied by fusion > input

        • The break-even point is defined as an operational state where the energy given to the system to maintain its reaction is equal to the energy produced by the same system.

          To ignite the fusion reaction described in this article, they have to expose the canister to pulses of neutrons and generate ultrasonic waves. Both processes require a total energy Ei. The energy returned by the system is in the form of neutron emission. Those neutrons have an energy Ef. The break-even point is reached when Ef = Ei.

          P
          • Yes, but total energy returned would be how much energy is released by the reaction, and would probably not include how much of that energy we could actually use. The two numbers are NOT equal.
            • You are right. The energy returned by the system needs to be converted in another form like electricity before we can use this process as an energy source. The efficiency of the conversion process is always lower than 100%.

              This is why the authors are now looking for applications which need a source of neutrons. Hence, they do not need to convert those in another form of energy.

    • RBFA (Score:5, Insightful)

      by p3d0 ( 42270 ) on Monday April 19, 2004 @09:15AM (#8903408)
      Read both articles. The "burned" link talks about applications.

      It's actually the better link. Not sure why the submitter chose to relegate it to second-class status.

    • Re:Usefulness? (Score:5, Interesting)

      by radtea ( 464814 ) on Monday April 19, 2004 @12:20PM (#8905446)
      To give you an idea of the scale here, the energy per neutron in any fusion reaction is a few MeV. This scale is set by the fundamental physics and can't be altered. 1 MeV = 1/1.6E-13 J. To produce 1 W you would therefore need to produce ~1E13 neutrons/s on a continuous basis. They are producing ~1E6 neutrons/s in bursts.

      Ergo, they need to scale up by about a factor of 1E7 to have a 1 W reactor, and 1E13 to have a 1 MW reactor (sufficiently powerful to supply the energy needs of a few thousand typcial North American homes.)

      These are not small numbers. Offhand, I can't think of any technology that has successfully spanned this many decades from proof-of-concept to practical reality. Even going from an early Chinese gunpowder rocket to a Saturn V booster didn't involve such an impressive scaling up.

      --Tom

      • Re:Usefulness? (Score:3, Informative)

        by Strange Ranger ( 454494 )
        > I can't think of any technology that has successfully spanned this many decades from proof-of-concept to practical reality.

        How about The Marquand Logic Machine [ibm.com]?

        That's a pretty impressive scaling up over the last 12+ decades.

      • Re:Usefulness? (Score:4, Insightful)

        by Mysticalfruit ( 533341 ) on Monday April 19, 2004 @04:20PM (#8908499) Homepage Journal
        Who says it has to scale up that much?

        What if the scale up is so you can have something the size of a mini fridge in your cellar that creates energy for just your house?

        Plus the reactors created thus far have been to study the principles, not attempt to harness them.

        Any production reactor is going to be designed to maximize it's efficency, not maximize the viewability of the reaction.

        • Re:Usefulness? (Score:3, Informative)

          by michael_cain ( 66650 )

          What if the scale up is so you can have something the size of a mini fridge in your cellar that creates energy for just your house?

          For a commercial power plant, you need 10s or 100s of megawatts. For home, probably less than 10 kilowatts peak, less than that if I have a flywheel or other way to store power for peak demand periods? Call it 4-5 orders of magnitude saved. There are some additional potential savings in a distributed system; you can in principle do away with the transmission losses we suf

          • True but I don't want to deal the radiation from backyard fustion. And I think it would be cheaper to do it on one huge device vs many small ones.
      • you do realise that 10^13, even 10^20 is a very small number in some comparisons (when 1g of most stuff contains about 10^23 atoms).

        by the same argument, fission should have never worked, as for instance U235 only produces about 180MeV per reaction (i.e. only about one order of magnitude more than a D fusion reaction).

        So it's all about the threshold of a self-sustaining reaction. Once you get that under reasonable conditions, scaling up is not so bad.
  • I will be the first to admit that I didn't understand the finer details in that article, but the premise is rather exciting.... in another 10 or 20 years. It is a great breakthrough, however, whether or not you understand the science...
  • 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?
    • Ever feel the warmth of the sun? Lots comes of nuclear fusion.
      • I mean our artificial nuclear fusion experiments (peaceful ones-i.e not H-bombs).

        Nothing comes of them.

        Although I agree a lot comes off the Sun :)

        • Re:We hear this all the time (Score:5, Interesting)

          by R.Caley ( 126968 ) on Monday April 19, 2004 @09:26AM (#8903492)
          I mean our artificial nuclear fusion experiments [...] Nothing comes of them.

          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.

          • actually JET in 1997 (Score:5, Interesting)

            by mzs ( 595629 ) on Monday April 19, 2004 @11:45AM (#8904922)
            I do not know about Princeton but the JET Experiment [parliament.uk] reached Breakeven in 1997. Spot-on about the neutron production issues though.
          • 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.

            ObOldJoke: Some years ago, a student paper allegedly proposed that the fusion reactor architecture most worth pursuing was a Gravitational Confinement [usgs.gov] design.

            The kicker is that he may be right (you could powe
          • 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.

            They have yet to get a Tokamac to break even for more than a single run; the complexities are too much. They say that as they scale up this will be less and less of a problem...

            As far as neutrons; the main problem isn't the waste material, it's transmutation of the reactor itself. They choose the e

    • Re:We hear this all the time (Score:5, Informative)

      by Bazzargh ( 39195 ) on Monday April 19, 2004 @09:18AM (#8903436)
      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 [iter.org] 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.
    • Wouldn't it be funny if eventually, the bubble-fusors DID reach break even, but could only produce a very low power density. For instance a huge plant being required to generate enough surplus energy to blowdry someone's hair.

      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?

  • Fusion, Cool! (Score:5, Insightful)

    by RalphBNumbers ( 655475 ) on Monday April 19, 2004 @09:05AM (#8903324)
    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.

    • Hot pants (Score:2, Funny)

      by p3d0 ( 42270 )
      At first I thought you said "giant magnetic trousers".

    • Re:Fusion, Cool! (Score:4, Interesting)

      by Goldsmith ( 561202 ) on Monday April 19, 2004 @01:19PM (#8906357)
      That's the same sort of thing people were saying 60 years ago.

      When physicists started doing fusion research, the plasma chambers were about 3 feet on a side, and very easy to use (comparitively speaking). Most people didn't believe it would ever amount to anything, but everyone was in awe of the compactness, elegance and exotic behavior of the experiment.

      The scientests working on it probably said exactly the same thing these guys are saying: we see some energy out, we're not quite at break even, but we'll get there.

      After working with fusion guys for a couple of years, I know that this stuff gets complicated really fast. This bubble fusion technique is at the point laser fusion was at 15 years ago, which means it's about time everyone started taking it seriously. In a few years we'll be debating where to put the new, mega-huge bubble fusion test reactor, which will bring us, again, one step closer.

      Sometime in the next 50 years, one of these methods will turn the corner. The magnetic field people will figure out what to make thier vessel walls out of, the laser people will figure out how to make and shoot perfect hollow spheres of frozen DT, or these guys will overcome whatever unknown problem is keeping them from producing energy.

    • 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.

      Problem is, at the 'sane' average temperatures and pressures, all you get is low grade generalized heat, which isn't suitable for power generation. (Not to mention the fact that these sonofusion devices are about wher

    • This is one of the thing which I think will power the future (no pun intended).
      This particular unit though is in teh infancy of its scientific growth. In 20 years (maybe more or less who knows with certain technologies and random descoveries) everyone will have their own mini fusion reactor to power their own living units. "The power grid" will no longer make reference to homes but street lamps or something...if we are even in need of lamps being as how we most likely wont be controlling our vehicles.

      As wi

  • And you will know them by the trail of tritium (Score:3, Interesting)

    by jellyfish_green ( 605870 ) on Monday April 19, 2004 @09:11AM (#8903377)
    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.

  • Can someone tell me (Score:5, Informative)

    by bgins ( 446545 ) <bgins&hotmail,com> on Monday April 19, 2004 @09:35AM (#8903556)
    A brief summary of the sciencedaily page:

    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 was curious to see everyone's response to this (well, everyone that has a better idea of the implications of this working, that is) and i'm surprised there aren't more posts!

    Is this a sign that we've stopped caring about "cold fusion"? Is the fact that this field has had a less-than-credible past hurt this discovery? Is this a discovery? Have movies like Chain Reaction [imdb.com] spoiled us into thinking that this is a pipe dream?

    Somebody help me out.

  • Next Step - 1,000 Atmospheres (Score:5, Interesting)

    by PIPBoy3000 ( 619296 ) on Monday April 19, 2004 @11:16AM (#8904558)
    From the Business Week article [businessweek.com], 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 [ccnr.org].

    • Re:Next Step - 1,000 Atmospheres (Score:4, Interesting)

      by mstorer3772 ( 526790 ) on Monday April 19, 2004 @11:38AM (#8904827) Homepage
      I would think that at higher pressure, the bubbles wouldn't expand as much, so you wouldn't get any extra energy that way.

      However, at higher temperatures, things could get "interesting". And at higher pressures, water's boiling point rises, so I guess we'll see.

      Or they might try a liquid other than water, one that exists only at much higher temperatures... something like liquid Titanium. That's, what? 3500 farenheit? How hot does uranium have to get to liquify?

      Make that 3034 F... oh and apparently tungsten is way up there too, with a melting point of 6192 F. Yow. Oh, and according to webelements.com, uranium melts at 2070F, and boils at 7101F. Uranium gas? That sounds unpleasant.

      And I'm assuming that all that temperature data holds true at 1 atmosphere, piling on a couple thousand bars (or pascals or whatever) ought to drive those numbers up further.
      • They're using a liquid called "deuterated acetone" as the liquid. From the science daily article [sciencedaily.com]:

        The acetone contains a form of hydrogen called deuterium, or heavy hydrogen, which contains one proton and one neutron in its nucleus. Normal hydrogen contains only one proton in its nucleus.
      • Or they might try a liquid other than water

        The problem being that bubble fusion depends on water. Basic physics here; Tin is the most stable element. Everything with an atomic level less than Tin is capable of fusing and releasing energy. Everything with an atomic level greater than Tin is capable of fissioning and releasing energy.

        Titanium, tungsten, uranium, none of them would support fusion.

        You know what the best element to fuse is? Hydrogen. The best isotope? Hydrogen-2. The liquid they are u
        • It is generally stated that iron is the most stable element, not tin. I once read a science fiction story that made the odd claim that silver was the most stable.

          In high school, I did the calculations using CRC data, which implied that an isotope of nickle was even more stable than iron. It was a small difference, and perhaps I made a mistake. Or the CRC data might have been off.

          In any case, this is the first claim I have seen for tin being the most stable element, and I doubt it.
    • "with the possibility of inexpensive and clean energy"

      Eh... Fusion byproducts take decades rather than fission's centuries to loose their radioactivity, but I still wouldn't call it "clean".

      But who knows? Maybe this technology will hit over-unity at higher temperatures and pressures.

      I guess we'll just have to wait and see.

    • Re:Next Step - 1,000 Atmospheres (Score:5, Funny)

      by PylonHead ( 61401 ) on Monday April 19, 2004 @12:07PM (#8905210) Homepage Journal
      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

      I'm sorry. We prefer to keep the main page of slashdot for unconfirmed loony perpetual motion devices.
      • "I'm sorry. We prefer to keep the main page of slashdot for unconfirmed loony perpetual motion devices."

        Goddamned kneejerk skeptic. RTFA - the phenomena has been replicated. There's definately something there.

        Now, any speculation about any purported wonderous applicaions of that phenomena could be treated as vaporware.

  • Would this work better in microgravity? (Score:4, Interesting)

    by caffeinated_bunsen ( 179721 ) on Monday April 19, 2004 @11:40AM (#8904868)
    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).

    • Re:Would this work better in microgravity? (Score:4, Insightful)

      by Ayaress ( 662020 ) on Monday April 19, 2004 @12:29PM (#8905594) Journal
      I don't know if it would work any better, but good luck getting the poloticians that run the major space programs to launch your inconvineiently large laboatory complex into orbit so you can try it out.

      Anyway, if it could work in microgravity, I'd have to wonder what it would matter? It certainly could power a large space station if we ever build one, but what about power on the ground? About the only way to get the power back down to earth would be something like microwave transmission, and I'm assuming that at least some of the aforementioned politicians have played SimCity, and won't let you run anything involving microwave power transmission or Godzilla in a populated area.

    • No? (Score:4, Insightful)

      by barakn ( 641218 ) on Monday April 19, 2004 @05:43PM (#8909354)
      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've heard Taleyarkhan speak... (Score:5, Interesting)

    by gardyloo ( 512791 ) on Monday April 19, 2004 @02:02PM (#8906933)
    I was at a conference of the ASA [aip.org] 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!
  • Did anyone see Chain Reaction? Sound waves help create fusion that looks likes bubbles in water?

    Anyone? Anyone?

    Did he patent it yet? Hurry Keanu, hurry!
  • The DD reaction requries ~35 keV to initiate, while the DT requires only ~4 keV -- an order of magnitude less energy. So why did they use DD?

    I worked with Purdue's bubble fusion system for a bit. We used DD because of the near impossiblility of getting tritiated-acetone. The deuterium in the reaction comes from the acetone in which all hydrogen atoms have been replaced by deuterium atom. The generated heat is hot enough to break down the acetone an start the reaction.

    Deuterated acetone is hard to come
  • I heard about this a few years ago in popular (science? mecahnics?).

    They called it sonolumenecense or something like that. It didn't produce fusion at the time but they thought it might be a possibility

    Good to know some cool wacky experiments come to fruition.

    From 1998 check out http://www.ans.org/pubs/journals/fst/vol/34-2-128- 136.html

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