Laser Fusion Put On a Slow Burn By US Government 143
gbrumfiel writes "Those hoping to laser their way out of the energy crisis will have to wait a little longer. The U.S. government has unveiled its new plan for laser fusion, and it's not going to happen anytime soon. It all comes down to problems at the National Ignition Facility (NIF), the world's most powerful laser at Lawrence Livermore Lab in California. For the past six years researchers at NIF have been trying to use the laser to spark a fusion reaction in a tiny pellet of hydrogen fuel. Like all fusion, it's tougher than it looks, and their campaign came up short. That left Congress a little bit miffed, so they asked for a new plan. The new plan calls for a more methodical study of fusion, along with a broader approach to achieving it with the NIF. In three years or so, they should know whether the NIF will ever work."
Re:Another lie about the NIF (Score:5, Insightful)
what lie? the lab and government make no secret work done there in both fields, controlled fusion and thermonuclear bomb research.
stop using the word miffed (Score:4, Insightful)
Besides being an ugly word it is imposing a sort of emotional response to something that is more practical and dare scientific.
At the end of the day we have created fusion. Most of it came through bombs, but from a scientific standpoint we know about fusion.
This is about creating a clean, reliable, cost effective energy solution.
There should not be hard feelings or even a feeling of failure. The idea was sound enough to look into. Maybe it's just not practical. No use throwing good money after bad or crying over spilled milk.
Re:stop using the word miffed (Score:5, Insightful)
If we're suggesting words to stop using, I would like to nominate "boffin". A "boffin" is the term that a British journalist, apparently unable to distinguish an astronomer from a geologist, uses to describe someone who uses their brain in their job (as opposed to a British journalist).
Re:Fusion future (Score:4, Insightful)
If we want to get serious about global warming, we have to make mining and burning coal a capital offense, and shut down every mine and plant with the urgency of eliminating the slave trade.
Instead, even eco-minded Germany is ramping up coal production and consumption because they started shutting down their reactors. There is a *new* 2200 MW coal burning plant in Germany. They foolishly believe that the competition is between nuclear and wind, and prefer wind (I do, but it's not remotely enough), and find that when actual joules have to be counted to keep the lights going, the coal gets burned.
the only long term solution is solar (Score:2, Insightful)
Re:Fusion future (Score:5, Insightful)
That's a great plan if you want to kill just about as many people as global warming will(possibly more).
Fundamentally the survival of modern humanity is dependent on our access to energy. With access to sufficient energy we an survive most anything(including a 5 degree temperature rise, heck we even know how to destroy nuclear waste if we have enough energy to do it), without it, we're pretty well boned. Now I'd love to see coal phased out as soon as is humanly possible, but in a world where nuclear is off the table in most places and base load renewable energy is still unproven as far as I'm aware, we don't have that luxury. What we need is something which can replace coal without forcing us to drastically reduce either the reliability or supply of electricity. All indications are that fusion might be the energy holy grail, and we're going to need one.
Practical aneutronic fusion is likely impossible (Score:4, Insightful)
Hello, I'm sorry to say this, but aneutronic fusion is probably never going to be a practical energy source.
There's a reason D-T fusion is the focus. One problem is that all the aneutronic fusion reactions involve higher-Z (higher atomic number) nuclei. Higher Z nuclei have worse energy loss via Bremsstrahlung radiation than the D-T or D-D reactions. In a plasma hot enough to sustain fusion reactions, the electrons and ions are banging against each other, and every hit potentially makes X-rays or gamma rays, converting thermal energy into light. In a reasonable-sized thermal plasma, these photons pretty much just leave without interacting again, thus cooling the plasma.
People have calculated that the energy loss rate from Bremsstrahlung in a thermal plasma composed of atoms capable of doing aneutronic fusion would exceed the rate that the fusion reactions would heat it. Thus, the plasma would cool right off, the flame would in effect "go out" because it would lose heat faster than it created heat via fusion.
In a star, this works out, because a star is so very, very big that the photons from Bremsstrahlung are re-captured within the star: i.e., the heat can't escape because of sheer mass in the way. We're never going to pull that size and density off in a lab or an engineering installation.
Now, if you can somehow arrange for the plasma to NOT be thermal, you may be able to beat this issue. However, keeping a plasma from thermalizing requires a large energy input, and is very hard to arrange for and preserve long enough to get energy from fusions. Inertial confinement might work (laser or Z-pinch or the like), there you potentially have very high densities for maybe "long enough" for Bremsstrahlung not to eat your lunch: I don't know. However, both laser and Z-type installations seem very hard engineering problems.
The wikipedia on "aneutronic fusion" discusses these issues some as well.
Anyway, that's one reason most are happily ignoring aneutronic fusion entirely. Another is that much higher temperatures are required for the aneutronic fusion reactions, and we haven't even got D-T going yet and that is the lowest temperature fusion reaction. D-T is where I would put my money, too, given the results of the physics calculations.
--PM