Alan Boyle wrote a very interesting article about the National Ignition Facility (NIF) in Lawrence Livermore National Laboratories in Northern California. Look at the Flash video on their website - it's cute. See also Google News. Recall that their aim is to ignite fusion with the help of 192 very powerful lasers.
NIF was featured in this 10-minute part of the BBC's "Horizon" program (with Brian Cox). See also How NIF works on YouTube.
At any rate, their most recent tests indicate that they may ignite the fusion and extract more energy out of it than what they pumped into it - if their "thumbnail" success is naturally extrapolated. These good news were reported in a Science article:
Glenzer et al.: Symmetric Inertial Confinement Fusion Implosions at Ultra-High Laser EnergiesDeuterium-tritium capsules (gold-plated hollow cylinders called "hohlraum" for "hollow area" in German) may be compressed and implode. Of course, at least years will be needed for commercial versions of the technology even if it works.
What does the extrapolation - the missing steps - require? They used small hollow areas and only achieved 3.3 million °C - for Al Gore: it's the temperature you believe to be found inside the Earth. They need 100 million °C which could be achieved with bigger capsules compressed by the factor of 1,000.
To avoid the fate of NIF's ancestor, the Nova Laser Facility (where the fuel escaped in one direction before the fusion could possibly start), they need a very uniform or isotropic inflow of energy. To do so, they have also invented a new trick - changing the frequency of light at the laser cone's center.
Even if the shots are successful, they would have to be repeated 10 times a second to make a good power plant. To summarize, we don't know whether the lasers, or the tokamak-style ITER in France, will be more successful. Mixed fusion-fission are also being investigated (LIFE).
Besides real hopes that fusion can be achieved, NIF is also useful to learn things about astrophysics, safety of nuclear stockpiles, and other things. There is also a sociological point of doing these experiments: without them - and without nuclear tests - the nuclear community could also very well go extinct.
We will see whether the extrapolation and "marginal" improvements can actually be done. Because as a classic joke says, fusion is the energy source of the future, and it will always be. :-)
If you were able to get to this point, you should also click at "fusion" below and look at 14 articles on this blog about fusion.