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| SANDIA NATIONAL LABORATORIES |
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.
Fusion is a nuclear reaction that releases energy not by splitting heavy atomic nuclei apart—as happens in today’s nuclear power stations—but by fusing light nuclei together. The approach is appealing as an energy source because the fuel (hydrogen) is plentiful and cheap, and it doesn’t generate any pollution or long-lived nuclear waste. The problem is that atomic nuclei are positively charged and thus repel each other, so it is hard to get them close enough together to fuse. For enough reactions to take place, the hydrogen nuclei must collide at velocities of up to 1000 kilometers per second (km/s), and that requires heating them to more than 50 million degrees Celsius. At such temperatures, gas becomes plasma—nuclei and electrons knocking around separately—and containing it becomes a problem, because if it touches the side of its container it will instantly melt it.
"Holding my nose, and diving deep": the first paragraph sounded like cold fusion, but Science published it, so I'll wish them well, and print the results - successes or failures, as this proceeds.
AAAS: Z machine makes progress toward nuclear fusion, Daniel Clery
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