The achievement does not mean that fusion is now a viable power source. Being able to study the conditions of ignition in detail will be “a game-changer for the entire field of thermonuclear fusion,” says Johan Frenje, an MIT plasma physicist whose laboratory contributed to NIF’s record-breaking run. In reaching scientific breakeven, NIF has shown that it can achieve “ignition”: a state of matter that can readily sustain a fusion reaction. Energy Secretary Jennifer Granholm said at a Washington, D.C. “Simply put, this is one of the most impressive scientific feats of the 21st century,” U.S. Fusion researchers have long sought to achieve net energy gain, which is called scientific breakeven. Though the conflagration ended in an instant, its significance will endure. In a tiny blaze lasting less than a billionth of a second, the fusing atomic nuclei released 3.15 megajoules of energy-about 50 percent more than had been used to heat the pellet. The pellet compressed and generated temperatures and pressures intense enough to cause the hydrogen inside it to fuse. On December 5, an array of lasers at the National Ignition Facility (NIF), part of the Lawrence Livermore National Laboratory in California, fired 2.05 megajoules of energy at a tiny cylinder holding a pellet of frozen deuterium and tritium, heavier forms of hydrogen. For the first time, a fusion reactor has produced more energy than was used to trigger the reaction. Today, researchers announced a milestone in this effort. For more than 60 years, scientists have pursued one of the toughest physics challenges ever conceived: harnessing nuclear fusion, the power source of the stars, to generate abundant clean energy here on Earth.
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