The Key Number: 3.88 megajoules.
The experiment in December generated a whirlwind of accolades when it produced about three megajoules of energy — equivalent to about 1.5 pounds of TNT, or about 1.5 times the energy of the incoming lasers. It was the first time that a fusion reaction in a laboratory setting produced more energy than it took to start the reaction.
The July experiment was essentially identical to the December one. “We expected a similar yield,” Dr. Town said. “On the order of three megajoules.”
The actual output was 3.88 megajoules.
The better-than-predicted result indicates that with a few tweaks, laser fusion can become markedly more efficient. But minuscule variations could yield fusion duds as well.
A fusion experiment in June, just a month earlier, was also predicted to produce about three megajoules, but it generated only between 1.6 and 1.7 megajoules, Dr….
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