Slashdot Mirror
Low-power table-top fusion
SEWilco writes "Lawrence Livermore National Laboratory scientists described Tuesday producing fusion with a mere million-dollar machine. It was described at this APS Centennial session.
Bursts of neutrons are detected, the hallmark of fusion that
`cold fusion' was missing" Update: 03/27 02:27 by S : In somewhat related news,
muggs wrote in about
a new laser-based method for
watching atoms bond. It relies on using X-ray diffraction
patterns to locate the moving atoms.
I'm just curious about how the energy output of this thing compares to the energy required to power the laser. From reading the article, I'm pretty sure that it absorbs more than it releases, but if its not too big a difference, just a little more work could possibly turn this into a much bigger deal.
The article states (well, infers) that the intended purpose of the device is to produce neutrons, not to provide power.
HSJ$$*&#^!#+++ATH0
NO CARRIER
Phil Farnsworth, who invented TV, sold out most of
his interest in TV and went on to be a borderline
crackpot with something called the Farnsworth
Fusor well into the 1960's -- it was a
similar-sounding fusion device. Others thought
that he was on to tomething. (See "The Farnsworth
Chronicles" somewhere on the web) Anybody know how
much connection there is between Farnsworth and
this project?
GE demonstrated fusion at the NY World's Fair in
1964. They had some giant device that would charge
up all kinds of coulombs, and then k-blamm -- a
big flash and a bang -- and they would announce
that fusion (but probably only a half-handful of
nuclei or so) had taken place. Same story, lots
of energy in, little energy out. But still there
are scientific uses for the neutrons.
Analog magazine had an article a few months ago
describing how to duplicate Farnsworth's fusion
system with roughly high-school level physics lab
equipment. Recommended. Wear your lead BVDs.
A while ago, when I was a lad, doing 'A' level physics (16 to 17 years old), I did some research into renewable energy sources, to discover that some people consider the holy grail of renewable energy lies in the field of genetic engineering, and since hearing their ideas, I tend to agree. Some may consider it a `Frankenstein science', but just for a moment imagine a world where a photosynthesis reaction provides the decomposition of water to its base elements, hydrogen and oxygen. These may then be re-combined in an exothermal reaction to provide heat. Bearing in mind that it is heat which powers almost all continuous electricity generation to this day -- granted some hydro-electric power (eg. the Dinorwig plant in Wales) provide extra energy to the National Power Grid during eg. the cup final -- whithout which there'd be no WWW, no /. and I'd never have found out that it was researchers not far from home who discovered cold fusion.
Oh yeah, I mentioned a derivative of fusion energy. Well it's the Sun that fuels the plants that would energise the reaction, and we all learnt in school that the Sun is only the solar system's biggest ever fusion reactor.
PS. Why the nick? Well it's the mutt's nuts!
I worked at Princeton U's Plasma Physics Labs around '80-82 as a tech. The motor/generator set for the TFTR (last one built) weighed 270 tons, if that's any indication of why the "desk-top" part is cool about this story.
:-)
Now THAT was a cool job. That's where I first saw a trackball. It was hand-size, military-looking with two buttons at the top, and we had to build the interface ourselves.
Uphill in the snow, both ways.
The revolution will NOT be televised.
I have read a bit about the Farnsworth fusion devices.
They weren't crackpot "fringe science," but ultimately they lost funding when just about everything was focused onto magnetic confinement (pardon the accidental pun, please).
Farnsworth's device worked by rerouting electron beams and creating a spherically shaped region of electric potential that would trap protons and cause them to fuse.
I think if you fueled it with deuterium, it would produce neutrons but not break even.
There are about a zillion different ways of producing fusion at about this stage of development, i.e. throw a bit less than a million dollars at it, (probably in Farnsworth's case, a lot less), and produce neutrons, but not approach breakeven.
I think some of them might be a lot better than Tokamaks if they received Tokamak-level funding.
Phil Fraering "Humans. Go Fig." - Rita
(currently testing something about signatures here)
Geez, these guys should win an award for finding a more expensive method for doing the same job worse than an existing technology.
A few years ago, you could buy a pulsed neutron generator (model 811-A) from Schlumberger-EMR Photoelectric for about US$100000. (I believe that was the correct price.) It could generate 2x10^8 neutrons per second when operated at 100kV. (Of course the duty cycle isn't a full second.) Some laboratory neutron generators have achieved maximum neutron fluxes of 1.4x10^12 n/cm^2/sec.
The oil industry uses these things for well logging. You can measure the porosity of rock strata with neutrons by counting the number of neutrons reflected by the interstitial water. You lower one of these things down a borehole along with a neutron detector. You pulse the source and count the number of neutrons reflected back to your detector as a function of time. The more porous the stratum, the longer you see neutrons being backscattered.
Fred Bacon
Aerodyne Research, Inc.
(but not speaking for them at this moment.)
I personally wouldn't want to be anywhere near a fusion explosion of a "half-handful of nuclei or so" -- or where you talking about how many you could count on one hand?
Of all things...fission.
Currently, fission requires a critical mass of fissionable material. This is because you need the neutrons that a fission reaction gets to hit other fissionable material to keep the reaction going.
If tabletop fusion becomes cheap enough, you could put it in the center of a subcritical mass of fissionable material and stop relying on the fission reaction to supply its own neutrons. It would be fail-safe as well, because you stop the reaction by turning off the laser.
And the above may result in tabletop _fission_. Usable as a power supply or a weapon. Atomic-powered airplanes, or nuclear SAMs to shoot them with. Either way, I'm scared.
--The basis of all love is respect
Here's why you should not be happy about this story. This device doesn't produce useful fusion energy, but it does produce hot neutrons, and it does so cheaply. What good are hot neutrons? They can be used to transmute non-fissionable isotopes of into fissionable isotopes.
Fissionable isotopes are rare. Denying third-world bohemian have-nots access to fissionable isotopes is the linchpin of our nuclear non-proliferation strategy. Therefore, if someone can easily cook up fissionables in his basement, then a future imperialist meddling in some irrelevant nowhere country's civil war could provoke a nuclear response by the Elbonians.
Be afraid, be very very afraid.
Fusion that occurs in the hearts of stars does so at a relatively high temperature. Millions of degrees. Various fusion research projects focused upon somehow replicating this temperature on earth. (This is relatively hard to do unless a nuclear explosion is going on in the immediate vicinity.)
"Cold Fusion" demonstrations took place at room temperature. Since room temperature even in August w/o air conditioning is far less than several million degrees is so much cooler (relatively speaking) as to be deemed "cold."
Cold Fusion would be a Bad Thing, too, since it would permit Bad Guys to build nuclear weapons materials using their Mr. Fusion power generators' neutron flux.
btw, after the Elbonians cook up cheap fissionables, they can design their nukes using Beowolf clusters of 486s.
Sleep well, America.
How many people would like to see more articles like and less on Linux, the latest OSS flamefest, star wars, katz, etc.? I'm not saying do away with those topics, but geez, if I want the Linux Today, I know where to find it. (On the right hand side of my /. screen, of course. :-)
SPF support for most open source mail servers can be found at libspf2.
Well, I just got back from Atlanta and the meeting about an hour ago. It was great. Stephen Hawking spoke on "The Universe in a Nutshell" and I saw many friends, mentors, and even my thesis advisor running around.
As a friend would say, it was a "geek fest". I spent the plane ride back with an acquaintance talking about his research. Funny how much interest there is in this stuff... only if there were... ya know... JOBS in it?
Ok... ok. Most of the stuff talked about would put the most hardy computer geek to sleep. I dont think anyone here cares much about floppy modes of macromolecules, or CCSD calculations, or non-uniform sampling of distributions in Monte Carlo simulations in order to examine rare events (some of the talks I went to). But on the other hand, there were some very cool talks, and a large number of nobel laureates, not to mention some really cool exhibits.
How does any of this tie into the slashdot effect?
In a nutshell, think of the slashdot effect (SE) as an avalanche, or a statistical mechanical critical exponent problem. Once a link is posted, it is only a matter of a short time (tau) that this information gets out, and in short order you get a polynomial in tau times something like exp(-t/tau) people following that link. Thus, the target of the link, with a server that is not configured to deal with recognizing the first derivative of this number of people as a function of time, falling over and coughing uncontrollably until it starts doing things like
dd if=/dev/null of=/dev/hda bs=65536
Properly set up servers frequently check slashdot for existance of links, so they have measurements of tau, and estimates of the polynomial. With this in hand, they can detect a slashdot avalanche, and quitely disconnect the port...
Ok, its been a long day, with one canceled flight out of Atlanta...
Under the "Fusion vs. Fission" part of the ABCNEWS fusion article (at the bottom), they say "one million millionths of a second"!! Last time I checked, that can be written as "one second".
It's in the third or fourth paragraph, depending on whether you count the first sentence as a paragraph or not.
Slashdot's first reaction to VMware
Several points and concepts I can think of:
This definitely points at the fact that a low powered(relatively) setup can *start* the fusion process, while a secondary setup and process would maintain it, whether it be tokamaks or more lasers and such.
Another point about the efficiency; it needn't truly be able to generate more energy than it uses if some way of tapping into non-useable energy(such as heat or solar) can be used. Imagine a system that is 92% efficient, but if 10% of the energy needed to operate the system could by harnessed by solar collectors in orbit, and we only need to provide 90%, the 2% difference would then be useable by us, with the remainder used to power the system.
Just a thought
AS
-AS
*Pikachu*