Table Top Fusion Courtesy of Tiny Bubbles

Erik Baard writes: "The peer-reviewed journal Science is carrying a cover story about the possibility of table top fusion. Not cold fusion, mind you, but the apparatus might look that way to some. Oak Ridge and other labs say they have gotten the fingerprints of fusion (neutron production) from collapsing bubbles in liquid, a process that heats a local area to temperatures as hot as the surface of the sun, and releases photons. The disputes are already here -- notably from Dr. Robert Park of the American Physical Society and from critical reviewers who say they haven't repeated the neutron production. But the authors say the critics didn't calibrate their equipment correctly. Articles regarding the discovery can be found on Eureka Alert " CD: Looks legit, but Pons and Fleishman (and the University of Utah for that matter) talked a good game. I suppose I'll belive in tabletop fusion when a generator comes atached to my next laptop. The author of this post also has a longer article up at the Village Voice

Comments

MMMmm Sonoluminescence

[cronik]

Sonoluminescence: an Introduction

Single Bubble Sonoluminescence HOWTO

Since sonoluminescence dosent seem to scale up (to my knowledge) this seems like a moot point. It is sort of cool to have a cheap way to study micro-fusion though.

Downloadable copies of the articles

[Zunt]

PDF copies can be downloaded from here.

Re:Not likely

[vondo]

Not really. Advance copies are usually provided before publication. These are usually available well before the article appears in print. It's certainly not considered unfair to comment on a scientific article in this manner and it happens all the time.

You'll notice the journal and/or the authors have announced the results to the media ahead of the print version being available too.

It's not like a TV station scooping a daily paper out of a story they researched or something like that.

BTW, I wouldn't consider him a professional nay-sayer, but rather skeptical, analytical (both good qualities in a scientist) and out spoken (which can be good or bad).

Want to make some fusion yourself?

[danox]

You too can make sonoluminescence happen. Try it with some deuterium and see if you can get fusion. Sound complicated, just use this easy to follow guide. It will give you step by step instructions for reproducing that special kind of magic that is sonoluminescence. All you need is:

• sinus generator: (sounds a bit painful)any function generator working around 25kHz, adjustable to +/-1Hz (+/-10Hz may work, too)
• amplifier: nearly any kind of audio amplifier will do. If you're not sure, measure the saturation voltage: 40V peak-to-peak should be enough.
• 2-trace oscilloscope
• 2 piezoceramic Transducers (drivers):around d=16mm in diameter, h=8mm thick
• piezoceramic pill-transducer (microphone):around 3mm in diameter, 1mm thick
• three finger clamp
• laboratory stand
• flask:take a 100ml Pyrex/Duran spherical flask, diameter 65mm, with a small neck. An industrial one has poor optical quality, so better take a free blown one.
• coil(s): around 20mH, see text
• resistors: 1M, 10k, 1R
• coaxial cable
• quick-drying epoxy glue
• an eyedropper or a syringe (one of those little do-it-yourself subcutaneous is very good)
• degassed distilled water:
• • Pyrex/Duran Erlenmeyer flask (0.5 or 1l) and airtight stopper with pipe, rubber hose and clamp to close it
    or
  • aluminium/highgrade steel drinking bottle (0.5 or 1l) with screw cap; one of those found in camping stores, a bare one without varnish
• a bubble ;-)

oh, and it is nice to have:

• second oscilloscope
• vacuum pump
• high-pass filter
• laser

Go for it kids. By the way, my favourite part is this quote: "Increase the driving voltage until you hear a horrible screeching noise, which sounds like your flask is going to crack. Don't be surprised if it does".

I have to fill in some more text here, becasue slashdot sais I have too few characters per line. Well its just a bloody list of things. Of course there won't be much to each line, what do you expect?

Paper in PDF and Abstract

[skwang]

Here is a link Science Magazine is providing:

Science Magazine

It has a pdf version of the article in question. Here is the abstract.

In cavitation experiments with deuterated acetone,tritium decay activity above background levels was detected.In addition,evidence for neutron emission near 2.5 million electron volts was also observed,as would be expected for deute- rium-deuterium fusion.Control experiments with normal acetone did not result in tritium activity or neutron emissions.Hydrodynamic shock code simulations supported the observed data and indicated highly compressed,hot (10 6 to 10 7 kelvin)bubble implosion conditions,as required for nuclear fusion reactions.

Bubble temperatures are not well-known.

[jinx90277]

I worked briefly with sonoluminescence at UCLA when I was a student there several years ago. Dr. Seth Putterman is one of the notable names in the field, and wrote a wonderful piece in Scientific American a few years ago detailing how to make your own sonoluminescence apparatus at home. This article surprises me quite a bit, however, since the temperature of the bubbles is hardly a matter of consensus.

The evidence for fusion-capable temperatures inside a sonoluminescing bubble lies in two main categories:

1. You can examine the emission spectrum of the bubble. The spectrum is continuous, with a peak which depends on a variety of factors (noble gas content, temperature of the fluid, etc.), so you can try to figure out the temperature based on the emission expected from a blackbody of a similar temperature. The last I heard, the temperature was at least an order of magnitude less than what you would need.
2. You can run simulations which make assumptions about the bubble collapse mechanism. If the bubble remains perfectly spherical during the collapse, then you may get the temperatures being quoted in the article. But there are other theories for the collapse, and requiring the bubble to remain perfectly spherical during a violent collapse doesn't seem intuitively obvious to me.

It's been a few years since I worked with this stuff, so take this with a grain of salt, but I'm not optimistic about this paper being validated.

Re:Fusion: Efficient and dangerous

[Guppy06]

"If the creation of nuclear technology became this simple, it not only gives terrorists an easier method to attain nuclear energy, but a way to actually create it themselves."

People like you are going to drive me prematurely bald...

Fusion reactors != fusion bombs

Fustion reactors are so damned far removed from fusion bombs that it's been about 50 years since we developed the second and we still haven't figured out the first. I'm willing to bet it will take at least another 50 years after the development of fusion reactors before we can make a fusion bomb that doesn't require a fission bomb to actually get the thing to go off.

"While it's true that a nuclear explosive based on this current method wouldn't spread as much harmful radiation as a uranium based explosive,"

You're right about that, but you have no idea how right you are.

First and foremost, the act of fission frees neutrons from their parent atoms. A lot of neutrons. Enough neutrons to set off the fission reaction. Fusion generates far fewer free neutrons (if at all, depending on your fuel) because it's busy trying to form atoms instead of breaking them apart.

Secondly, when people think of "radiation" from a bomb they think of the fallout (since the actual radiation from the explosion lasts as long as the actual explosion). Fusion in and of itself has no fallout. The fallout from modern hydrogen bombs is from the fission bomb that's used to set it off. No fission bomb, no fallout.

"it's potential damage far outweighs that of a dirty bomb."

Now here is where you need to lay off the crack pipe.

Getting a fission reaction to start is pretty easy: get a neutron-producer close to a clump of unstable atoms. Getting a fusion reaction to start, on the other hand, requires a LOT of input heat in the beginning in order to generate the plasma the reactions takes place in. So much heat that the pressure at the heart of Jupiter isn't enough to start a sustainable reaction. In the past 50 years the only way we've been able to pull it off is with a fission bomb.

But let's pretend that a pure fusion bomb is possible in the short term. Although it's possible to squeeze a fission bomb into something the size of a suitcase, your average 20 megaton device is more or less a cubic meter in size. But it's only that small because the heat generator is a tiny little suitcase-sized fission bomb. If we try to use a fusion reactor to generate the heat instead of a fission bomb, I don't see the device being small enough to fit into a cargo container (probably the largest possible size for a device to be useful to terrorists).

But what if they try to blow up a fusion power plant? Fission reactors are heavily shielded to keep the inside in. Probable fusion reactors would be heavily shielded to keep the outside out. If a tokomak loses magnetic containment, the plasma expands, cools, and reverts back to a gas. If it loses its physical containment, air gets in, conducts/convects away heat from the plasma, the plasma cools and reverts back to a gas. If you try to blow it up you just end up with a negligible amount of hot gas on top of the explosive.

Personally, I'd be a hell of a lot more frightened of an attack at a coal-fired plant. Have you ever seen what a spark can make coal dust do? Or what about popping off the fuel tanks at a natural gas power plant? And while I'm on the subject of boiling liquid-vapor explosions, oil refineries look awfully unprotected...