Last year on a December morning, scientists at the National Ignition Facility at the Lawrence Livermore National Laboratory in California (LLNL) managed, in a world first, to produce a nuclear fusion reaction that released more energy than it used, in a process called “ignition.”
Now they say they have successfully replicated ignition at least three times this year, according to a December report from the LLNL. This marks another significant step in what could one day be an important solution to the global climate crisis, driven primarily by the burning of fossil fuels.
NIF’s target chamber is where the magic happens — temperatures of 100 million degrees and pressures extreme enough to compress the target to densities up to 100 times the density of lead are created there.
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at NIF, scientists fire an array of nearly 200 lasers at a pellet of hydrogen fuel inside a diamond capsule the size of a peppercorn, itself inside a gold cylinder. The lasers heat up the cylinder’s outside, creating a series of very fast explosions, generating large amounts of energy collected as heat.
The energy produced in December 2022 was small — it took around 2 megajoules to power the reaction, which released a total of 3.15 megajoules, enough to boil around 10 kettles of water. But it was sufficient to make it a successful ignition and to prove that laser fusion could create energy.
Since then, the scientists have done it several more times. On July 30, the NIF laser delivered a little over 2 megajoules to the target, which resulted in 3.88 megajoules of energy — their highest yield achieved to date, according to the report. Two subsequent experiments in October also delivered net gains.
“These results demonstrated NIF’s ability to consistently produce fusion energy at multi-megajoule levels,” the report said.
There is still a very long way to go, however, until nuclear fusion reaches the scale needed to power electric grids and heating systems. The focus now is on building on the progress made and figuring out how to dramatically scale up fusion projects and significantly bring down costs.
