To remain at the cutting edge, U.S. fusion researchers must participate in the huge international experiment called ITER being built in Cadarache, France. But to pay for ITER—which aims to produce a self-sustaining fusion reaction, or "burning plasma," and prove that fusion is a viable energy source—the United States may have to sacrifice the very community of researchers who would use the machine when it is ready. That paradox hit home last week, when President Barack Obama submitted a 2013 budget request to Congress that would slash the nation's already beleaguered domestic fusion program while boosting the U.S. contribution to ITER.
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