Another possibility--the most disturbing one, actually--is that the North Koreans had been telling the truth when on May 12, just two days before South Korea detected the high levels of xenon, they announced they had created a nuclear fusion reaction, a step necessary to the building of a thermonuclear device.

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In fact his trick (and the reason why it might be possible to produce a nuclear reaction in such a small piece of apparatus) is that what he does propose is not really fusion at all.

ECONOMIST: A novel form of fusion power: Psst, kapow! | The