1.21 Jiggawatts!
January 20, 2005 9:44 AM   Subscribe

Researchers Report Bubble Fusion Results Replicated. Bring on the Mr. Fusion, please.
posted by loquacious (46 comments total)

 
Is this 'cold' fusion? If so, does this bring it back from the grave?
posted by loquacious at 9:46 AM on January 20, 2005


As a liberal arts major, I read the release with a modicum of comprehension. As loquacious asks, it's unclear how much energy is being used to create the fusion, but if it's not "cold" fusion, it would seem to be "not very hot" fusion. Eagerly awaiting the Mefi science brigade.
posted by jalexei at 9:54 AM on January 20, 2005


Speaking of grave... who wants to put on a tin foil hat and make bets about when these scientists will mysteriously vanish/die?

All kidding aside (well, mostly kidding, there really have been some mysterious/shady incidents surrounding discoveries like these) - there is no mention of power input versus output, nor is there mention of cold fusion, so I'm guessing that this is not as huge a stepping stone to Free/Cheap Power Forever (tm) as we'd like to think.

Still an interesting article, and a worthwhile post. Thanks, poster.
posted by twiggy at 10:00 AM on January 20, 2005


Cool fusion?
posted by tpl1212 at 10:01 AM on January 20, 2005


It's not cold fusion. It's very definitely hot fusion.
posted by Ethereal Bligh at 10:02 AM on January 20, 2005


Cool fusion!
posted by Divine_Wino at 10:03 AM on January 20, 2005


My understanding is that they are using sound waves to collapse a bubble containing a "fusable" gas. See also Sonoluminescence. The bubble collapses with such force that it produces some amazing physical effects, even in ordinary lab conditions. I never understood how exactly they would harness this energy, but it is still a cool experiment.

Scientific American published a how to for doing this at home a few years back, but I can't seem to find it anymore on the web.
posted by phatboy at 10:04 AM on January 20, 2005


Wikipedia also has a good summary.
posted by phatboy at 10:11 AM on January 20, 2005


Sonoluminescense is also related (thought not exactly the same) to the spark you see when you chew Wint-O-Green lifesavers candy. Cavitation is a pretty neat thing in general.
posted by odinsdream at 10:20 AM on January 20, 2005


I studied sonoluminescence (which is exactly what this seems to be) a few months ago, and at that time the consensus was that we did not know what the hell was happening therein (the Navier-Stokes equations are a bitch), but fusion did not seem the likely candidate, but a possible one.

I am rather surprised to see such unequivocal claims about this in SciAm. Have to see if I can track down the journal article.

But even if it is fusion, it is not at all clear how one would put it to good use. Exciting nonetheless, though.

(By the way, I have the SciAm article on DYI sonolumi that I could email to anyone interested. It involves a set of $100 piezoelectric transducers, a spherical flask, a frequency generator with fairly fine adjustment, a decent sized inductor for tuning, and 'scope to monitor it all, plus the skills to wire/solder it all up with coax and the patience to tune the hell out of it and get it right).
posted by teece at 10:23 AM on January 20, 2005


I'll believe it when it sustains critical mass for a week without a Jrun error...
posted by mkultra at 10:30 AM on January 20, 2005


What's different about this and from the study of sonoluminescence in general is this part:

neutron emission

High temperatures and photons from sonoluminescence is one thing, this is that and something much more.
posted by Ethereal Bligh at 10:31 AM on January 20, 2005


Pro fusion or Con fusion?

I can't make up my mind.
posted by Floydd at 10:35 AM on January 20, 2005


Bligh, bubble fusion is an application of sonoluminescence studies. Reaserchers noticed in the the late eighties, early nineties that the colour temperature of the flashes was in the same ballpark as that needed for fusion. This bubble fusion is a direct refinement of the sonoluminescent technique.

This idea was quite controversial ten or fifteen years ago---I know of at least one assistant prof denined tenure because his collegues didn't believe in sonoluminescence. He produced quite an adequate number of papers, had lots of funding and students, but the chairman of the department cut him off at the knees because the tenure committee refused to accept his research. This was also, just after the whole cold fusion fiasco, and nobody wanted to be the next on the dirty end of the APS tar-brush.
posted by bonehead at 10:54 AM on January 20, 2005


from the article: The research team used a standing ultrasonic wave to help form and then implode the cavitation bubbles of deuterated acetone vapor.

Y'know, I did this in the kitchen the other day when I was making pancakes. (When the cavitation bubbles of deuterated acetone vapor appear around the edges, flip the cakes over and cook for 2 more minutes.) I though this was pretty standard breakfast-prep practice. Had I only known of the potential applications!

Ah, well. It makes for light, fluffy flapjacks, in any case.
posted by Dr. Wu at 10:55 AM on January 20, 2005


Thanks, Ethereal Bligh, I had missed that in my first skim over.
posted by teece at 11:04 AM on January 20, 2005


100 million K is definitely not "cold" fusion.
posted by caddis at 11:06 AM on January 20, 2005


Um, do note that the date on this is March 2004. It's not exactly breaking news — even if it is damn cool.
posted by Johnny Assay at 11:13 AM on January 20, 2005


Luminous Life Savers?
All this time I've been saying Light Sabres.
posted by weapons-grade pandemonium at 11:14 AM on January 20, 2005


Is it just me, or is the publication date on that article quite a long time ago?
FOR RELEASE: IMMEDIATE
March 2, 2004
posted by lowlife at 11:17 AM on January 20, 2005


Seems to me that making this useful would involve creating a controlled amount of bubbles over a sustained time in sufficient volume to generate the kind of heat it takes to boil water, generate steam, and turn turbine dynamos.

However, that would depend on how much energy is being put in to create the ultrasonic wave as opposed to how much heat is coming out. The article doesn't mention that. Clearly the bubbles are very small and the 100 million Kelvin temps last for only a short time. But it does seem to me that because of the energy conversion of the fusion, that it's entirely possible to liberate more nuclear energy from from the fusing deuterium and/or tritium than is necessary to maintain the standing ultrasonic wave.

Very interesting! And if usable, could really save our collective asses... practical fusion in less than 40 years would be nice.

And indeed a "Mr. Fusion" might actually be possible; a small device using this process is easy to imagine. Tho I don't think you could drop a soda can and banana peels into it...
posted by zoogleplex at 11:19 AM on January 20, 2005


Apparently, these findings by the team from Oak Ridge, Purdue, RPI and the Russian Academy of Science are hotly contested by others in the field, including others at Oak Ridge.
posted by caddis at 11:20 AM on January 20, 2005


bonehead, it does seem that all this is a refinement of what has been usually called sonoluminescence, for sure. The neutron emission may not even be unique to this experiment, the difficulty has always been taking accurate measurments of the phenomonen, which is what seems to have been the major feat of this team. I am eager to get myself a copy of the article.

It is also interesting to see how wrong most of the people I had read were, as the writing I had access to was very much against the idea of fusion. But if this press release is right, these guys have gone a long way to proving it.

They didn't mention sonolumi in the press release, and I bet I know why: they want to stay away from that Keanu Reaves movie as much as humanly possible (Chain Reaction, ah, quality).
posted by teece at 11:21 AM on January 20, 2005


caddis -

AFAIK, "cold fusion" doesn't refer to the amount of heat produced. If there is no heat, there is no energy - all fusion will produce huge quantities of heat (or it would be useless as a power source). Cold fusion means you only have to put in a fraction of the energy that you get out of the reaction, which has been the roadblock since fusion was first discovered.
posted by chundo at 11:22 AM on January 20, 2005


Oops, that last cite related to the 2002 work. This article details the somewhat less opposition to the 2004 work.
posted by caddis at 11:25 AM on January 20, 2005


Measuring neutron emission is notoriously difficult---bad neutron measurements were one of the fatal blows to the cold fusion claims. To many physicists who were around in '89, these claims drag up all kinds of eerie parallels. If they really do have tritium though, they may actually be on to something.

On preview: nice articles, caddis. thanks!
posted by bonehead at 11:33 AM on January 20, 2005


I am not sure that "cold fusion" has a dictionary definition. I always thought it referred to the work of Fleischmann and Pons. They used an electrochemical process at room temperature. They never heated, even locally, their materials to many millions of degrees as is happening in the bubble fusion.
posted by caddis at 11:38 AM on January 20, 2005


Cold fusion means you only have to put in a fraction of the energy that you get out of the reaction, which has been the roadblock since fusion was first discovered.

As I understood it, the "cold" in cold fusion referred to the temperature at which the reaction was supposed to occur. Pons and Fleishman claimed that their fusion occurred by a mechanism other than that generally observed (in stars, hydrogen bombs, and plasma confinement reactors). I'm not sure how detailed their theory was, but it had something to do with the localization of deuterium atoms in a metal lattice...

If fusion does occur during cavitation, it would be occurring at temperatures similar to those typically observed, by the same mechanism as other well-known fusion reactions.
posted by mr_roboto at 11:39 AM on January 20, 2005


This is scraping the bottom of FARK's barrel. It was ho-hum news even last March.
posted by fleener at 11:50 AM on January 20, 2005


Bligh, bubble fusion is an application of sonoluminescence studies. Reaserchers noticed in the the late eighties, early nineties that the colour temperature of the flashes was in the same ballpark as that needed for fusion. This bubble fusion is a direct refinement of the sonoluminescent technique.

Did I say otherwise? No, I did not.

The point I wanted to get across was this: sonoluminescence can be used to cause fusion; not that sonoluminescence causes fusion.
posted by Ethereal Bligh at 11:57 AM on January 20, 2005


An aside: the post's title really ought to be 1.21 Gigawatts not "Jigawatts," as it stands. A couple of years ago I read Isaac Asimov's excellent book The Measure of the Universe (Powell's, Amazon (under 2 bucks!)) and found the Good Doctor telling me one pronounced the metric system prefix giga "JIG-uh," which immediately brought to mind the crazy Doc from Back to the Future . . . and a sense of dread. Was Asimov not wrong here? I mean, I had been mentally making fun of Doc's JIG-uh-watts for fifteen years. Rush to dictionary. Rush to several dictionaries. And fuckin'-A right Asimov was, too. Lookee here. Now of course, I say "GIG" with the bookended hard G's like everybody else, but I mentally cringe when I think somebody may be laughing at ol' Doc Brown for saying aloud correctly something we all now say wrong. (I dunno whether loquacious meant to make fun of anything or not; I just know my reflexes kicked in. Jig is up! Jig, Jig, Jig uh BYTE.)
posted by cgc373 at 12:00 PM on January 20, 2005


Meanwhile, US to be Aussie nuclear dump.
posted by homunculus at 12:01 PM on January 20, 2005


cgc373, that's geniunely interesting - thanks for the trivia.
posted by odinsdream at 12:39 PM on January 20, 2005


Kewl- my alma mater is linked in an FPP on MeFi.
posted by Doohickie at 12:41 PM on January 20, 2005


Homunculus, what is the relevance of that link to this conversation? Answer: none
posted by Ethereal Bligh at 12:43 PM on January 20, 2005


The point I wanted to get across was this: sonoluminescence can be used to cause fusion; not that sonoluminescence causes fusion.

Ethereal Bligh, I think actually we don't know the answer to that question. It has been posited from the very beginning that the simplest of sonolumi could be fusion. There was some research that said no way, but there was no definitive answer either way, because of the extreme dificulty in measuring what was happening in a pretty small space on extremely short time scales.

It is quite possible that fusion is the cause of sonolumi all the time, and all these guys have done is found a reliable way to measure the phenomenon and prove it. Or they could be wrong and sonolumi could be something else.

But there is no definitive answer about what causes sonolumi that I am aware of, merely many competing theories. And this experiment is remarkable in actually measuring neutron emissions, but it may not be remarkable in producing them: for all we know that was happening all along and it was just too hard to detect.

Or are you aware of some research that definitively shows how "plain" sonolumi works?

(Completely from memory and without reading their paper, but the key to this research might be the use of acetone vapor, as the initial use of liquid water, while cheap and easy, was problematic as the water also happened to act as a rather effective shield, stifling measurement abilities).

But in all respects, what is described here looks like plain, vanilla sonolumi amped up with a deuterated acetone vapor and observed by good measuring equipment.
posted by teece at 1:42 PM on January 20, 2005


ITER gets closer to reality? Or are they using a different method, all this science stuff both intrigues me and confuses.
posted by TwelveTwo at 2:12 PM on January 20, 2005


S.M.I.(squared)L.E.

S.M.I.2L.E.

All that is needed is a clean renewable source of energy.

Please work!! Much more than I hoped that the Titan probe would function, I sure as hell hope this is something fruitfull.
posted by Balisong at 2:26 PM on January 20, 2005


Sonoluminescent fusion with plain water?? That surprises me. What kind of temperatures would you need? If it's photons that we've been seeing, which is obvious from the name, those are plenty damn easy to create, right? :) So I don't understand why fusion would be on anyone's top-ten list of things that are probably going on during sonoluminescence-not-involving-deuterium. IANAP, of course. You are, I assume, so please help me out.
posted by Ethereal Bligh at 3:00 PM on January 20, 2005


And fuckin'-A right Asimov was, too.

He usually was.
posted by rushmc at 3:15 PM on January 20, 2005


Well, except about the mutants with emotional-control abilities.

As far as we know.
posted by zoogleplex at 4:35 PM on January 20, 2005


Sonoluminescent fusion with plain water?? That surprises me. What kind of temperatures would you need? If it's photons that we've been seeing, which is obvious from the name, those are plenty damn easy to create, right?

Fusion has certainly always been one of the leading contenders to explain sonolumi, although many have been skeptical. Initial estimates of temperature were very high for regular, single-bubble sonoluminescence performed in water ( I forget the exact number, but I think it was the same order of magnitude described in this experiment: 100K K). The difficulty was getting a good spectrum analysis of the light emitted, because at a critical point water begins to absorb any photons that may or may not have been created.

So yeah, fusion from plain water was posited, but never proven, as far as I know. The photons emitted are the byproduct of something happening as the bubble collapses.
posted by teece at 6:53 PM on January 20, 2005


Yet another wrinkle in a long-standing (some say ridiculous controversy--the last I heard was that fusion was absolutely not a byproduct of cavitation. I actually performed a single-bubble sonoluminescence experiment as an undergraduate using this popular DIY apparatus--it is an extremely rewarding lab project. I promise to MeFi that I'll print out the paper and post later tonight some thoughts about this result, but briefly:

Bligh, the absurdly high temperatures only need to be present over a very small volume (say ~ 10 nm^3) for a very small time. The process is fast enough that the surrounding material doesn't thermalize. Plain water works because at the moment of cavitation the water vapor inside the bubble briefly becomes plasma (this part, at least, is not disputed) and then it is a matter of high temperatures to get the hydrogen to accept more nucleons. That said, all the spectral evidence is consistent with more moderate temperatures (~10's of thousands K) where fusion will not happen.

Teece The measured spectrum (blue light when Argon is dissolved; a single bubble is very visible to the naked eye) has been the key evidence that fusion is most likely not happening. What photons do you believe are being absorbed, UV? Regular chemistry and the proper thermodynamic treatment give the exact spectrum observed. The remaining smoking guns for small amounts of fusion byproducts is gamma-ray detection synchronous with an acoustic collapse and low levels of tritium. Though some tritium was detected in an earlier experiment, the goofballs didn't bother to have a control sample of water in identical containers with no application of sound waves.

More later.
posted by fatllama at 8:44 PM on January 20, 2005


Oh, and zoogleplex, you're completely onto it: it is hard to imagine this device breaking even as an energy source. The effect is rare, if it is happening at all (unless this new result is a huge change). Watts of acoustical energy go into the standing waves and end up making mostly light and heat. In order to jump on this bandwagon, you need to believe that the few gammas that come out of the rare fusion events will be enough to heat a neutron absorber (but not the acoustical cavity!) enough to make steam (or power a thermocouple) which drives a turbine and makes the aforementioned Watts of sound.

Get the fusion rate up---way up---either with a catalyst or different fluid and then we can have a Mr. Fusion FPP.
posted by fatllama at 8:55 PM on January 20, 2005


The measured spectrum (blue light when Argon is dissolved; a single bubble is very visible to the naked eye) has been the key evidence that fusion is most likely not happening. What photons do you believe are being absorbed, UV? Regular chemistry and the proper thermodynamic treatment give the exact spectrum observed.

Perhaps the research I read was dated, I had a hard time getting access to current stuff. But the stuff I read definitely pointed to problems in spectrum measurement, and blockage of UV might have been it, don't really remember. I trust you if you say that's the way it is, for now, but I doubt the issue is settled.

I was interested in sonolumi not as a source of fusion, but just in understanding why it happens. Which, to my knowledge, we still don't have, fusion or not. Do you know of any breakthroughs in explaining what is going on?
posted by teece at 9:27 PM on January 20, 2005


Ok. I read the paper (the full citation is Taleyarkhan, R.P, et al. Phys. Rev. E 69, 036109 in case anyone is bored and has access to a university library) last night. As far as scientific papers go this one is extremely readable even to laymen (perhaps not the section on the calibration of the liquid scintillator) so don't be afraid to look it up. The important evidence is all presented graphically and clearly. I'll note that nearly a year elapsed between when the paper was accepted and when it was finally published, which along with the large acknowledgements section implies that it was heavily reviewed. Despite the Macbethian curse that hangs over this topic, here's a short summary.

The Oak Ridge group has detected fusion in deuterated1 acetone at a highly statistically significant level (25 standard deviations) using three independent methods: neutron emission time-correlated to the acoustic collapse, gamma ray emission time-correlated to the acoustic collapse, and the presence of tritium2 after the fact. The neutron production rate is fairly small, 4(10)^5 per second, which could yield about 0.14 microWatts assuming 2.2 MeV per neutron. So this ain't Mr. Fusion.

The effect in question does not occur with kitchen-variety single bubble sonoluminescence. Their sample is completely degassed beforehand, and small bubbles are nucleated at the standing-wave anti-notes with a well-timed pulsed neutron beam. This exotic loading scheme allows the use of huge acoustic powers to expand the vapor bubble from a radius of R ~ 10 nm to R ~ 1 mm (this is gigantic compared to the factor of 10-100 increase in radius occurring in cavitation experiments I am familiar with). The shock wave produced by the initial collapse of this bubble can be heard by the experimenters (!) standing outside the shielded and enclosed apparatus.

The experimental controls are quite thorough and convincing. All three fusion signals (neutron, gamma, and traces of tritium) go away when: What is particularly interesting to me, and still unclear from just one reading with only a little background knowledge, is the following fact: the neutron and gamma emission signals are delayed ~ 10 acoustic cycles form the initial mega-cavitation event. This implies that the fusion is happening in the bubble cloud created by the initial cavitation and not during the ultra-violent initial collapse itself. I don't think the authors give any explanation for this but they do note that it is consistent with earlier results.

--
1 Deuterium is a heavy isotope of hydrogen; it has an extra neutron. Normal acetone is C3H6O, so deuterated acetone is C3D6O where the D stands for the heavy hydrogen. Similarly, water is H2O and heavy water is D2O.
2 Likewise, tritium is a heavier isotope of hydrogen; it has two extra neutrons.
posted by fatllama at 3:41 PM on January 21, 2005


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