Theoretically,that reaction should release a huge amount of energy from a relatively tiny amount of hydrogen. That’s the whole reason for working on the problem,and the physics works just fine. But it’s the engineering problem from hell,and in more than 50 years of experiments they’ve always had to put more energy IN than they got OUT.
Indeed,a long-running joke in the field has been that research on getting useful energy out of nuclear fusion is subject to the “Law of the Conservation of Difficulty”:whenever one problem is solved,a new one of equal difficulty emerges to take its place. But those days may now be over.
The big news from the Livermore Lab is that they focused 2.05 megajoules of laser light onto a tiny capsule of hydrogen fuel for a few nanoseconds and triggered an explosion – well,first an explosion,then an implosion – that produced 3.15 MJ of energy. That’s “ignition”:54 per cent more energy out than in.
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In scientific language,that’s “proof of concept”. Nobody really doubted that fusion could eventually be made to produce useful energy one way or another,but it still needed to be demonstrated in practice. Now it has been.
In terms of the actual energy output,however,it’s pathetic:about enough to boil one kettle. The heavy lifting of making fusion energy work on a huge scale at a commercially viable cost has still to be done,and the Livermore lab isn’t even working on that challenge.
Other people are,however,and the signs are promising. The biggest project is the 35-country International Thermonuclear Experimental Reactor (ITER) in France,a huge underground magnetic fusion device that broke ground in 2010,will go active in 2025,and should be producing really interesting results by the mid-2030s.