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Fusion In Sonoluminescence (Again)?
srhuston writes "According to a story at the NY Times (first born child req'd, yadda yadda), 'Scientists are again claiming they have made a Sun in a jar, offering perhaps a revolutionary energy source, and this time even some skeptics find the evidence intriguing enough to call for a closer look.' This has been covered here before (First, second, third) but it looks like they claim that the latest round of experiments, using better detectors, 'offer more convincing data that the phenomenon is real'." The scientists involved come from Rensselaer Polytechnic Institute, Purdue University, Oak Ridge National Laboratory, and the Russian Academy of Science; here's their press release.
*cough*google link*cough*
The claim is that the bubbles create temperatures high enough to create fusion.
--- Ban humanity.
... they squeezed tiny gas bubbles in the liquid so quickly and violently that temperatures reached millions of degrees and some of the hydrogen atoms in the solvent molecules fused, producing a flash of light and energy.
Please note that this is *NOT* cold fusion.
Iraq: war to save the U
"Going Supernova" requires a certain amount of mass. Our sun is too small. For a star the size of our sun, the death is a gradual swelling of the outer layers and a contraction of the core, resulting in a nebula with a white dwarf in the middle.
A drinking-cup sized chunk of fusion wouldn't have much umph at all. Considernig the processes going on are completely different from the kind in hydrogen fusion bombs, I'd say the worst explosion is from overheating and overpressurizing of the chamber - something like a handgrenade.
=Smidge=
Sonoluminescence: an Introduction
Single Bubble Sonoluminescence HOWTO
Actually after a while the walls of a tokamak have to be changed because neutrons makes them radioactive on the long run.
So yes this would produce radioactive material too, but a material less nasty and lesser material than a fission reaction.
Iraq: war to save the U
Actually:
"In this house, we obey the laws of thermodynamics!"
No electrons were harmed creating this post, though some may have been subjected to electrical and/or magnetic fields.
Perhaps I should clarify. We got these results when attempting to reproduce these results, which is why I doubt them. Our results were also consistent with our earlier results trying to estimate the peak temperature possible by sonoluminescence in a given fluid (which is, theoretically, unique for any particular fluid); both results were roughly an order of magnitude smaller than needed for fusion.
I've had this sig for three days.
Our maximum temperature for sonoluminescence in water was about 280 kK (kilokelvin). Our maximum temperature for sonoluminescence in seeded water (water + hydrogen, for example, although we used water + argon and water + helium; both gave similar results) was around 100 kK. I'll readily believe the second number can improve to approximate the first, but the first just isn't close.
In other substances, nothing seemed quite as good as water. Glycerine and alcohol were both within a factor of two; everything else was lower. Lower molecular density seems to give higher maximum temperature (although I'd have to check the theory to verify this isn't just a coincidence), so trying liquid helium might be cute... but I can't believe it'll help much.
I've had this sig for three days.
It's not just sustainability, it's getting it to react. You need intense pressures, and the only ways to do this previously, require very large (read: industrial) bits of equipment, just for the proof-of-concept.
If you mean "fusion in general", I'll accept that.
If you only mean to refer to sonoluminescence, then no, you do not nead large and expensive industrial equipment - You can do it in your basement with roughly $100 in equipment (though having a low-end oscilliscope helps, you don't absolutely need it, you could get away with a simple analog meter).
Check out the Single Bubble Sonoluminescence HOWTO for a nice, detailed example of a functional experimental setup.
Not exactly rocked science - As the basic idea, you make a flask of degassed water resonate at roughly 25khz. Insert a tiny air bubble, and bingo, with a bit of trial and error, you have sonoluminescence.
Of course, I agree that getting energy out of such a system may take some doing, but as a proof of concept (and just a really cool experiment in general), any advanced-amateur EE geek would already have all the parts they need.
ARG!! Must. Not. Answer...
A major difference between the sun and a large jar is mass and pressure. Stars must be larger than a certain mass threshold to be capable of a supernova event. At this time I forget what that threshold is but I do know that if Jupiter (sometimes considered a brown dwarf star) collapsed to become a true star it could not end its life in a supernova but it could produce nova events during its life span. The reason for this is that it does not have the mass to generate the inward pressure needed to suppress the outward pressure of the reaction. As the outward pressure builds up it will eventually become greater than the inward pressure, once it does it will become a nova. If the inward pressure is sufficiently powerful the star will begin to fuse higher elements (e.g. H+H=He, He+He=Li, etc.) and the outward pressure will exceed the inward pressure and in this case will result in a supernova destroying the star. A jar (or even an eventual facility based on this technology) simply is not massive enough to produce a supernova; this is what makes fusion as a power source so attractive. Without monitoring and adjustments the reaction simply ends. Our current fission systems do not require an artificial environment to make them function. I.E. the fission reactions have occurred naturally here on Earth and can have uncontrollable catastrophic results if not carefully monitored and adjusted.
NarratorDan
"If you're not confused by quantum mechanics, you really don't understand it." - Niels Bohr
The paper's going to be in Physics Review E, not Physics Review Letters, which is where your link led. Check out the first two sentences of the article:
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.
This approach, called bubble fusion, and the new experimental results are being published in an extensively peer-reviewed article titled "Additional Evidence of Nuclear Emissions During Acoustic Cavitation," which is scheduled to be posted on Physical Review E's Web site and published in its journal this month.
I did a search at the Physics Review E site, but it's not there yet.
Nevertheless, like you, I feel that the arrival of a press release before the paper appears is something of a red flag - Especially in this particular subfield of physics.
"The plural of anecdote is not data" -- Bruce Schneier
Maybe I haven't looked hard enough
It seems you didn't look at the press release at all. The sub-title of which being "Physical Review E publishes paper on fusion experiment conducted with upgraded measurement system". So, in case you have trouble interpreting that, what they are saying is that this has been peer reviewed, and it will be published, in a respectable journal.
Causing fusion is, in fact, not hard to do. Slash recently had such an article: College Freshman Builds Fusion Reactor. Unfortunately, it's getting the reaction to generate more energy than it consumes, is the problem. The bubbles may heat to 1 million degrees, but a few thousand atoms at a 1 million degrees will quickly lose its heat to the surrounding billions of atoms of matterial. This is why conventional reactors have been attempting to heat a large mass that is contained by magnets--the heat stays at those levels and hopefully enough heat can be tapped away to run some generators.
Bel, the mostly sane.. "Of course I can't see anything! I'm standing on the shoulders of idiots." -- Me
Yep. Less gas gives you higher temperatures, less light. It's a tradeoff. But for show-and-tell, more light is better. It's also much easier to figure out temperature with more light, and then project how temperature increases as the amount of gas gradually decreases; with no extra gas at all, trying to get a reliable spectrum was the most difficult thing I've done, and even then the error bars were huge. (For reference, with no extra gas at all, and degassed water, our original setup, as described, ticked a photomultiplier tube less than a million times a second. That's essentially the number of photons emitted over a significant (1% or so) portion of the sphere. Our next setup was built specifically to make that case more managable, but it was still sketchy.)
I've had this sig for three days.
Except that unlike cold fusion, the US Navy doesn't have researchers who have built working 200mpg carburetors and zero-point energy devices.
"...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
In all of the sonoluminesence work I've done, input power has been between 1 and 100 watts. I know people use both lower and higher power, but this is a very reasonable range.
With no additional gas, the bubble size is probably ROUGHLY 10^15 atoms (read as 10^10 - 10^20), depending on a million things. This is at a frequency of roughly (not quite as rough, but close) 10^5 Hz. Assume 10^18 deuterium atoms, for fun, and 0.01% D-D fusion. That gives you (roughly, what, 3.3 MeV for D-D fusion?) around 5kW to play with.
Understand that these numbers are rougher than back of the envelope... these are the kind you do when the envelope will never be found. But if you can pull off fusion at all in sonoluminescence (which is the question at hand), you're pretty much guaranteed decent return on investment.
I've had this sig for three days.
I think you're deep in the weeds.
Most radioactive waste from a fission power plant comes from decaying fission fragments - that is the left-over elements which are produced after the fissile material has split and released its energy in the form of the kinetic energy of the fission fragments which find themselves awfully close together with the same charge and not enough of the strong nuclear force to hold things together, plus the kinetic energy of the neutrons born from the fission process and some directly produced radiation.
These fission fragments then decay through a long decay chain up toward lead. Most of them have relatively long lives and produce high energy gamma so they create a problem.
Fusion power will also create fusion products - but those products tend to be more stable - grabbing neutrons from the stew and much more rapidly settling down into nuclides that are much less radioactive than those produced by fission.
Of course there ARE fast neutrons produced during the fission and fusion process. Neutrons born from fission are fast neutrons, very high energy. In all fission power reactors those neutrons have to be slowed into thermal equilibrium (lose a LOT of energy) by having elastic collisions with some material - say the hydrogen atoms in water (the material that slows the neutrons is called a "moderator") so they have a reasonable chance of interacting with another fuel atom and cause fission. U235 likes thermal neutrons to fission.
During the termalization process some neutrons will scatter out of the core, "leaking out" of the reactor core. And they interact with the primary shield. They make some things radioactive. The materials that go into reactor construction are choosen to reduce the nasty things that can get really radioactive - like, say, cobalt one of whose isotopes (Cobalt-60) decays giving off a very nasty gamma which lead doesn't shield particularly well. (another story).
So some materials will be irratdiated by the high energy neutron flux of a fission reactor and become radioactive. But the worst is done by the fission products of the reactor. Think one Curie of waste per watt of power at the end of core life as a thumb rule and remember that a Curie is one whale of a lot of radioactivity.
Firstly, is it something where they could have a whole vat of these bubbles being created and destroyed with sonic waves constantly and through this vat you could have water pipes that would create steam and drive a turbine?
This would not generate any extra energy. It is simply using energy to cause vibrations that heat up water and generate steam. The change in phase causes a high enough pressure to cause a turbine to generate electricity. In each of those steps, energy is wasted (it's the law!).
What the article is talking about is supplying enough energy to facilitate a reaction that could cause two hydrogen atoms to form a helium atom. When this occurs, the mass of the helium atom is slightly less than the sum of the two hydrogen masses. Since thermodynamics says the mass had to go somewhere, we account for the loss with an increase in energy (a la E=mc^2). The amount of energy released by this reaction is theoretically substantially greater than the energy used to force the two atoms together. At least, that's the gist of it.
Don't confuse fusion with free energy,however. Fusion comes at a price, and it's the coversion of mass into heat that leaves you with two less hydrogens and one more helium, so there still is a fuel that is 'burned'. Luckily, our favorite proton-electron duo is the most abundant element in the universe.
Heat is basically atoms bouncing around.
In bouncing around, they radiate a certain amount of energy incidentally as electromagnetics. This is called "black body" radiation, and is why hot metal glows red, and when hotter, yellow/blue. Colder metal, near room temperature, still glows-- in the infrared.
Lots of things at fairly "normal" temperatures (around 20C) have resonant frequencies of molecular bonds in the infrared and thus radiate in infrared. This is why you can use infrared to determine how hot something is, but the infrared is not the heat energy of the substance itself.
One of the big problems with fusion being energy-positive in a practical reactor is so much of the output energy is emitted on really high frequencies and exotic energy forms (x-rays, alpha/beta radiation, etc) because of the energy levels involved. These are difficult to turn back into useful energy to do work and keep the reactor running.
I don't know how it works but triboluinescence is distinct from nuclear fusion - it's probably a chemical reaction of molecules in crystals generated by mechanical energy that emits light. I don't believe triboluminescence results from nuclear fusion.
I don't know if the humor was intended or not, so excuse my humor detector if so...
Unlucky, however, is that most (all, afaik) man-made fusion reactions don't involve that proton-electron duo.
They involve heavy hydrogen (deuterium, hydrogen with a neutron) and heavy-heavy hydrogen (tritium, hydrogen with two neutrons), which is much more rare. The result, by the way, is not just one helium - it's a helium and a neutron for a net mass loss of about 2AU per reaction.
The activation cost of fusion using normal water is much, much higher than when using heavy water. There are processes to produce both of these isotopes (tritium can be produced as a side-reaction from the fusion, but deuterium must be filtered from water), but they're not especially capable of producing large quantities easily. But we've got to crawl before we can walk; once we get controllable, sustainable, and energy producing fusion, then we can worry about switching over to a fuel source that will actually make it practical to use for power.
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