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Z Machine Makes Progress Toward Nuclear Fusion
sciencehabit writes Scientists are reporting a significant advance in the quest to develop an alternative approach to nuclear fusion. Researchers at Sandia National Laboratories in Albuquerque, New Mexico, using the lab's Z machine, a colossal electric pulse generator capable of producing currents of tens of millions of amperes, say they have detected significant numbers of neutrons — byproducts of fusion reactions — coming from the experiment. This, they say, demonstrates the viability of their approach and marks progress toward the ultimate goal of producing more energy than the fusion device takes in.
Yes, and all the stars in the sky would have collapsed, and we would have created black holes at H-bomb test sites.
There might be nuclear waste to worry about given stray neutrons, but gravitons aren't something I'm worried about.
(T>t && O(n)--) == sqrt(666)
From TFA:
"Although the result shows that a substantial number of reactions is taking place—100 times as many as the team achieved a year ago—the group will need to produce 10,000 times as many to achieve breakeven."
In other words they aren't even remotely close to a meaningful breakthrough. Nothing to see here, move along...
Exactly in fission you are trying to hold the reaction back. That's why it can run away. Think of it like holding a dog against a leash. It the leash breaks the dog is gone.
Fusion is the opposite. It's like trying pull a mule. You can barely get the thing moving.
... A high school student working on a Farnsworth-Hirsch Fusor for their science fair project, capable of accelerating tenths of amperes, detects significant numbers of neutrons-byproducts of fusion reactions-coming from the experiment. This, they say, demonstrates the viability of their approach and marks progress toward the ultimate goal of producing more energy than the fusion device takes in.
Or not.
-- Insert witty one-liner here. --
...and here I thought this article was going to be about text adventure game engines. :(
http://en.wikipedia.org/wiki/Z...
Can you imagine if we put the war on drugs budget against fusion power instead? If we had started 40 years ago we might already have it.
uh... there's actually no minimum size for a star to collapse from to form a black hole. The only real requirements are that the star reaches the Fe phase at which point nuclear reactions become endothermic and the core collapses, rebounds at the neutron threshold, collides with the plasma outer shell sending that out and imploding with enough force to collapse again - this time beyond the neutron threshold. For a star with a start mass of ~1.4Msol, this would mean the core containing at least 50% of the stellar mass (0.7Msol) collapsing to a neutron sphere no more than 11 miles in diameter. The average mass of a Milky Way black hole is estimated to be 10Msol (or a start mass of 20Msol or thereabouts). The Fe+He phase (also known as the neutrino phase) of stellar evolution is estimated to last somewhere in the region of twenty millionths of a second and produces all the heavier elements in the universe in a supernova explosion. Less massive stars will die less violently, shedding outer layers over time and/or simply cooling. Few if any with masses less than about 0.75Msol will even reach the Fe phase before simply expiring. I do subscribe to the notion that Jupiter is a failed star, particularly given that it does radiate more than it receives from Sol.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
Really all you need is Flashblock. I install Flashblock, I see 0 video ads on text sites.
ObTopic: But if you install Flashblock and try to use the Z Machine, you'll have to click before Flaxo will start.
What the Z machine does is zap a little metal box of wires that may contain fusionables with a high voltage/current pulse that is stored in a really enormous bank of capacitors. Naturally that destroys their target and makes kind of a mess in the process.
I think they manage 8 shots/day if they're lucky.
8 shots/day is a far cry from a reasonable power flux. I'm not sure current pulsed power technology (not to mention other engineering) could stand doing this at some reasonable frequency like 1Hz without breaking down in a few minutes.
But at least they put a good fraction of the power input into the target, NOT like laser fusion--the lasers are horribly inefficient. (1%?)
-PM
You can't know that, unless you have foreknowledge of exactly which steps will have proven necessary to accomplish the ultimate goal.
Jupiter radiates more heat than it recieves not because it is a failed star, but because of gravitational contraction and something called differentiation, which is the layering of lighter and hevier elements sorting out (like dressing separating after you shake it).
The notion that Jupiter is radiating excess heat and, therefore, is a failed star is a tempting idea, but it is far from being a star. By an order of magnitude or three.
md5sum
d41d8cd98f00b204e9800998ecf8427e
I don't have any reason to believe this specific direction for fusion power is any good, but, yes, fusion power needs more funding if it's ever going to work.
The whole pulsed laser fusion effort turned out to be a cover for nuclear weapons research. It lets Lawerence Livermore study H-bomb like fusion reactions on a convenient scale. With a gym-sized bank of lasers aimed at a single point, they can pump enough energy into a tiny space to force fusion. That's a research tool.
So is the Z-machine, for much the same reason. It's yet another pulsed-fusion machine relying on inertial containment.
The tokamak crowd has at least been able to hold a fusion reaction together for 400ms or so. But plasma instability is the curse of all tokamak designs, including ITER. There's much doubt that ITER will work. It's conjectured that a bigger plasma will be more stable, but many physicists question this. ITER has become a pork program, though, and it's hard to stop. Cost is about $15 billion. If there was real confidence it would work, the private sector would fund it.
Right now, the new generation of stellerators looks more promising than the tokamaks.
My submission of a couple of days ago.
"The EM2 corportation has submitted a paper to axiv.org http://arxiv.org/abs/1406.0133 describing their $10 million US Navy project to investigate Bussards Polywell fusion device. NBC has a report on the development http://www.nbcnews.com/science... . Quoting Nicholas Krall, a plasma physicist who has been working in the fusion field for more than a half-century and has been an adviser to EMC2 Fusion, "I think this is the most exciting experimental advance that I've been involved in," he told NBC News. 'I'm stoked.""
Plus there are 2-3 other concepts that gave got Venture Capital funding. Fusion is looking more interesting.