How a US lab created energy with fusion—again

From Pop Sci.com (Aug. 13, 2023):

About eight months ago, scientists at a US-government-funded lab replicated the process that powers stars—nuclear fusion—and created more energy than they put in. Now, physicists and engineers at the same facility, the National Ignition Facility (NIF) at Northern California’s Lawrence Livermore National Laboratory, appear to have successfully created an energy-gaining fusion experiment for the second time.

NIF’s latest achievement is a step closer—the second step down a very long road—to a dream of fusion providing the world with clean, abundant energy. There is a long way to go before a fusion power plant opens in your city. But scientists are optimistic.

“It indicates that the scientists at [NIF] and their collaborators understand what happened back in December well enough that they have been able to make it happen again,” says John Pasley, a fusion scientist at York University in the UK who wasn’t part of this experiment.

NIF declined to comment, noting that the facility’s scientists had not yet formally presented their results. Until that happens, there’s a lot we won’t know about the specifics of the experiment, which took place on July 30.

There are multiple ways of achieving fusion, and NIF works with one, called inertial confinement fusion (ICF). In NIF’s setup, a high-powered laser beam splits into 192 smaller beams, showering a capsule that scientists call a hohlraum. Inside the hohlraum’s walls, this barrage spawns X-rays that crash into the capsule’s filling: a pellet of deuterium and tritium, super-squeezing it at temperatures and pressures more intense than the sun’s, initiating fusion.

The goal of all this work is to pass the break-even point and create more energy than the laser puts in: an achievement that fusion scientists call gain. In December’s experiment, 2.05 megajoules of laser beams elicited 3.15 megajoules of fusion energy. We won’t know for sure until NIF releases its data, but unnamed sources told the Financial Times that this second success created even greater gain. [read more]

Nice! Hopefully, the lab can scale up the fusion.