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Light and heat from NIF

hohlraum_12363.jpgThere’s plenty of press today about the National Ignition Facility (NIF), an ambitious project to drive fusion energy using a massive array of super-powerful lasers. If this sounds like some sort of devious James Bond plot, you’re not too far off: NIF’s primary job is to verify that the United State’s nuclear stockpile is working well.

But there’s also hope it could advance the cause of fusion power. NIF will fire 192 lasers onto a tiny capsule of hydrogen isotopes (deuterium and tritium). Scientists hope that the pressure exerted by all that laser light will cause the nuclei to fuse together, creating helium and a lot of energy.

This week, NIF announced a milestone: it successfully focused 0.7 megajoules of energy onto a test capsule. To hear some news outlets report it, you’d think this was the end of the quest for fusion energy. But scientists still must double the energy of the lasers and insert a deuterium-tritium fuel pellet into the machine before they can trigger a full fusion “burn”. Even then, it would be a long way from that to a fusion power-plant.

Even then there’s uncertainty: Nobody’s exactly sure whether NIF can concentrate its energy tightly enough. And if it can, contaminants from the capsule wall could disrupt the fusion process.

A couple of fusion researchers I spoke to about the NIF announcement were optimistic, calling it “very encouraging”. But for the most part they’ve still got their arms crossed—they’ll have to see higher energies and actual fuel in the machine before they’re convinced this US$3.5 billion gamble works as advertised.

If you’d like to learn more, I’d point you to the competition: Science’s Dan Clery has done a better job than most laying out what the milestone means, and what lies ahead.

Image: LLNL


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    sorgulama said:

    How can this series educate a child? i just dont get it..

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