Slashdot Mirror
Building the World's Most Powerful Laser
Bill writes "Lawrence Livermore National Laboratories is attempting to create the world's largest laser. The NIF's goal is to focus the laser on a pea-sized hydrogen pellet and result in fusion ignition."
It is not readily mountable on a shark's head.
If NIF achieves fusion ignition, it will for the first time in a laboratory simulate the pressures and heat of a nuclear explosion, allowing nuclear weapons scientists to study the performance and readiness of the country's aging nuclear arsenal without actually detonating a nuclear device.
...and his opinion matters why? Sounds like he's got a giant basis for bias. He continues...
Sounds good to me.
"If Congress knew it would cost $5 billion up front, would they ever have funded it? No way," maintains Christopher Paine, who has monitored NIF's development for the Natural Resources Defense Council, an environment advocacy group, and has been one of its sharpest critics.
Paine, who in a critique once dubbed NIF "The Unlovable Laser," maintains that NIF should follow the same path. He says it isn't needed and poses a nuclear proliferation risk because it might make it easier in decades ahead to develop new nuclear weapons, not just maintain existing ones.
Since, every American knows the only use of anything nuclear is to kill people. So now, we take a "reliable" newsource like CNN.com - and not only shred any chance of getting "unbiased" information and toss it in the can.
Also, to contrast that idiots opinion, we get:
The JASONs, a group of scientists frequently called upon to review complex defense or national security issues,
that sounds a LITTLE more relevant, no?
has concluded that NIF "does not represent a significant proliferation risk" and is "fully compatible" with U.S.
I guess this is why I can't appreciate the news for telling me anything new now adays. Someone go develop a computer to report things without bias, then I'll be interested in reading the news.
It might classify as the world's most intense laser target, but that's entirely different language.
Fusion ignition is also not the goal (or, for that matter, even the primary goal) of the laser cluster.. The intent is apparently nuclear weapons testing and design. Civilian fusion research is simply a pleasand side effect.
Free Software: Like love, it grows best when given away.
We're not really talking about a loss of efficiency in these things. The current stockpiles are based on high efficiency cores. We just don't make the "big hunk of uranium" bombs anymore. I would suggest a fascinating site for anyone looking for some good education. http://nuclearweaponarchive.org/index.html (Be sure to check out the Castle Bravo test.)
The cores on these things break down rather fast, and they aren't sure-fire to work correctly (or even behave themselves) after sitting on a shelf for decades. If we are going to keep them around, fine, but let's make sure we know what the things will do. Otherwise, get rid of them. There is no better way to cut yourself than working with a dull knife.
Nah, it's not even a little scary. Fusion is quite unlike fission, in that it's really hard to get going and just as hard to keep going.
With fission, all you have to do is put too much Uranium (or Plutonium or whatever nasty, radioactive stuff) in a closet, and it will spontaneously sustain itself in a "chain reaction". If you put way too much stuff in the closet, then the chain reaction runs away and explodes, spontaneously.
With fusion, you take a tiny sphere of deuterium (or tritium) and blast it for a tiny fraction of a second with the World's Largest Laser Beam. If you are really, really lucky, the deuterium will fuse to helium and you'll get out a little bit more energy than you spent getting the thing to fuse. There's no possibility of a runaway here, because there's no chain reaction. You can simply choose not to fire the WLLB at any point.
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The term "ignition" refers to the point of intensity of a fusion reaction whereby the high (kinetic) energy He nuclei fusion product is sufficient in power to heat any remaining fuel to the point of fusing itself. ie. when the reaction is capable of sustaining itself provided you continue to feed it with fuel. It is called Q=1. The NIF should achieve >Q=10 on a full system DT shot and this is called thermonuclear ignition and burn with "high gain". NOTE! the NIF will almost certainly NOT achieve breakeven (total power in Nd:glass lasers are disgustingly inefficient (~1%). Diode pumped Nd:glass is another story however and if a power plant is ever to be constructed using laser fusion then that is likely what will be used. They are still too fantastically expensive today though.
- "Hear that?! The percolations are imminent! Cease your ingress!"
yes its just another definition of ignition. spectrum of energy emitted by the H? I'm not sure I understand what you're after. If it is the energy of the products of the DT reaction you're interested in then its H-3 + H-2--> He-4 (with a kinetic energy of 3.5 MeV) and a hot neutron with a KE of 14.1 MeV. If it is the actual electromagnetic radiation from the hot plasma you are talking about then it just radiates like a blackbody at ohhh say 100 million degrees :o) which happens to be mostly in hard X-rays.
Incidentally, as long as I'm posting here I'd like to say that (no surprise really, its a science article) the AP article gets it a bit wrong. The NIF will never achieve the status of "most powerful" laser on earth. Highest energy laser on earth? At 2 MEGAjoules yes it will be the most energetic. But not the most powerful. The maximum power of the NIF is estimated at 500-750 Terawatts (trillion watts) (I'm approximating). However, the OMEGA EP laser which will be finished in 2007 (before NIF) will achieve a power of over 2 PETAwatts or 2 million billion watts. Several times that of the NIF.
- "Hear that?! The percolations are imminent! Cease your ingress!"
Ok, ok. I totally got this reference right away. Which maybe dates me a bit (I'm under 30).
:-)
A few people will usually get it. But the majority will say something amazingly stupid.
But what makes that movie (and that scene) so special?
Oh, come on! That's the ultimate 80's party movie for geeks! They pulled off all sorts of geeky pranks (dry ice in the hall, disassembling/reassembling a car in the dorm, tuning a radio to braces), saved the world through some pretty creative hacking/espionage, and even pulled an awesome prank on the bad guy! What's not to like?
Group think. Meh, original scenes make group think happen because the group remembers them.
Ummm... no. Group Think refers to the Slashdot mentality of accepting the story spin at face value without checking the facts. A perfect example was the Chase Mastercard story from a day or two ago. The poster said "wireless", "RFID", and "insecure", thus ensuring that 95% of the posts were "This sucks and is insecure wireless crap that I can hack like this RFID hack (some pointless link here)!" The truth of the matter was that the card was not wireless (induction), not RFID (smartcard), and was not insecure (crypto chip). It was actually a marked improvement over the current cards! And yet, the last response to my rebuttals of such nonsense still had someone calling it wireless and insecure! Enough to make me want to drop-kick a few people...
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Well, the easiest fusion reaction to do is the Deuterium Tritium reaction (DT). That is, it is the reaction which requires the "lowest" temperature to ignite. Thing is, most of the energy released in this reaction is in the form of hot neutrons. The percentage of the fustion energy released in the reaction as neutrons is called the reaction's "neutronicity" and is something like 80% for DT. This really sucks because neutrons, as you may be aware, are absorbed into the nuclei of the surrounding structure material, transmuting its constituent atoms into radioactive isotopes (albeit with relatively short half-lives). Soooo, the best idea around these days is to create a vacuum target chamber with ...wait for it.... undulating "waterfalls" of hot liquid lithium or "filbe" (Lithium Fluoride Beryllium Fluoride mix). The Li absorbs the neutrons and is heated in the process, the heat is then sent to boil water/run turbines, and the usual. There is a bonus in this scheme though, the Li after absorbing a neutron is transmuted into more Tritium! More Fuel! This is called the HYLIFE II reactor design.
- "Hear that?! The percolations are imminent! Cease your ingress!"
Riigghht. I'm not saying there isn't a reason for doing such a thing, I'm saying that the reasons stated make no sense. i.e. There's information missing somewhere here that would put the puzzle together. And you know what? I looked it up myself.
From this page, they are not using lasers for fusion tests as the anon poster suggested. Instead, they're using microlasers to do Spryton trigger tests. So no, nuclear scientists are not really, really stupid. Someone just has their facts out of whack (which happens).
If anyone *does* have a link to the military doing fusion testing with lasers, then by all means. Post a link!
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