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Nuclear Fusion Real Soon Now
Mr. A. Coward writes "Researchers at the
National Ignition Facility are attempting to produce nuclear fusion. They'll focus 192 amplified lasers on a pellet of frozen hydrogen. 'NIF experiments will be the first to create fusion that gives off more energy than it takes in.' That will have to be quite a bit, since it will take 500 trillion watts to ignite the pellet in the first place. The facility has been plagued with delays, and so far only 4 of the 192 lasers have been completed. Researchers believe they will first achieve fusion sometime around 2014."
Actually, once you've generated it and it puts out more than it received, you can recycle the process indefinitely. then its a matter of harnessing the output effeciently AND saving enough of the overage to eventually set a second chain of lasers firing, then in a few years the power output will grow exponentially and poof, free energy, mass space exploration, colonization, pure research civilization, galactic domination, intergalactic war with insect race, universal domination, peace and love and enlightenment, fin.
its kinda like putting a million bucks in the bank and living off the interest, but also putting aside enough of the interest to increase your returns.
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I know a number of people working on NIF and hear of its progress every few months. It's been plagued with problems largely due to budgeting, as scandals have hit the lab and much of the money was funneled out. The LLNL management was largely replaced due to these activities and for a while the entire laboratory was on the brink of being shutdown.
The four beams mentioned in the summary are really just a testbed. In the previous system, Nova, there was a smaller machine called Novet that had the same purpose. I always forget the newer machine's name, but this is standard practice versus a major delay. NIF is behind the original schedule, but that's due to problems (e.g. lens issues) and technical challenges always faced in such large R&D projects.
From what I hear, things will be going pretty well from now on. Since this is an international effort (led by the US), other countries are building their own versions. France has similar system that was brought up last year with help from LLNL personnel and has allowed the lab to avoid many of the same pitfalls the French have faced.
My main contribution to this thread is simply that NIF doesn't seem to be heading towards cancellation, like many government projects. The people behind it are extremely competent and far smarter than I am. The scandals are behind them and will be making steady progress. It's a really, really impressive effort.
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It's interesting that the NIF first full light is now pushed back to 2014. There's a small chance we may just beat them to ignigion.
I work at the Omega Laser(still the most powerfull in the world at 60 Terawatts! ya!) and there is currently construction going on here to complete what is called Omega EP(extended performance) by ~2007. Omega EP will produce an astounding 2.6 PETAWATTS(million billion watts!!) of power for a around a picosecond (so about 2-3 Kilojoules per shot which is much less than the NIF's megajoule scale shots) making it, by far the worlds most powerfull laser when complete. The new laser will use what's called chirped pulse amplification to produce its incredibly high petawatt scale power.
Using the current 60 beam 60 Terawatt (~30Kj) laser to compress a pellet of hydrogen fuel and then just before the moment of maximum inward compression and then stagnation; the EP petawatt beam will fire, producing an instant injection of Mev scale electrons directly into the center of the collapsing target and hopefully producing high fusion yeilds and perhaps even approaching ignition. The Gekko XII laser in Japan with its 500 terawatt scale CPA lser has validated this scheme, which is called "fast ignition", reporting that with the CPA laser used at maximum compression with their 12 beam 40 terrawat laser they've achieve an increase in neutron output(fusion yield) by 1 to 2 orders of magnitude...Can't wait till we can fire ours up!
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Oops I misspoke, I meant to say the Omega laser is actually the most ENERGETIC UV laser in the world at ~30Kilojoules/shot, Not the most powerfull, as there are a few other chirped pulse lasers with higher powers out there but not higher energies(most can only do a few hundred J per shot though this is still enough to do direct laser induced nuclear reactions).
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Essentially that's true, I suppose. NOVA was around 100 Terawatts per shot (I've heard it was capable of 100 Kilojoules per shot but I suspect it was actually less). NOVA only had 10 beams though and this ended up creating huge problems. When a pellet was imploded on NOVA the beam/beam instabilities and nonuniformity of the irradiation on target caused very large hydrodynamic instabilities as it imploded (Rayleigh-Taylor instability mostly) which spoiled the fusion reaction before it could really start.
The Omega laser with its 60 beams produces much higher irradiation uniformity and even though it's lower power than NOVA(which was decomissioned in '99) it holds the record for neutron production in a shot at something like 5X10^13 neutrons, indicating a much 'cleaner' convergence and fusion burn. There were several lasers at LLNL before the NOVA laser with various names like Janus, Argus and Shiva, which all used the fundamental frequency of Nd:glass lasers at 1064 nanometers(infrared) and the great contribution in the early '80s to ICF laser fusion by the Omega guys was the idea to convert this IR to its third harmonic at ~351 nanometers in the UV. This greatly increased laser absorption efficiency on target and consequently increased target compression pressures/temperatures accordingly. Allmost all high power Nd:glass lasers use this technique today.
- "Hear that?! The percolations are imminent! Cease your ingress!"