A year ago we reported on a breakthrough in energy research– creating the fusion reaction that powers stars here on Earth. It is now confirmed. Researchers at the Lawrence Livermore National Laboratory (LLNL) National Ignition Facility (NIF) achieved fusion ignition on August 8, 2021, with the results now been published in three peer-reviewed papers. The Physical Review Letters article has more than 1,000 authors, reflecting the team of scientists that built the first working nuclear fusion reactor. Though just for an instant, full fusion has finally been obtained!

Nuclear fusion is the process that powers the Sun and other stars: two hydrogen atoms fuse into one helium atom. This releases extremely large amounts of energy. It takes extreme conditions of temperature and pressure for fusion to occur, involving millions of degrees temperature and millions of atmospheres of pressure. The NIF accomplishes this by firing 192 lasers at a special target containing frozen hydrogen.

Fusion ignition is when a nuclear fusion reaction becomes self-sustaining, potentially generating more energy than was used to start the reaction, and continuing as long as there is fuel — in our Sun’s case, for billions of years. Fusion on Earth is also green energy, producing no radioactive waste other than helium, a useful element currently scarce on this planet.

The 2021 experiment (called a shot) yielded 1.3 Megajoules of fusion energy, about 6 times the amount that went into the microscopic target. To put it in more accessible terms, one megajoule is roughly the energy of a car traveling at over 100 mph.

“The record shot was a major scientific advance in fusion research, which establishes that fusion ignition in the lab is possible at NIF,” said Omar Hurricane, chief scientist for LLNL’s inertial confinement fusion program. “Achieving the conditions needed for ignition has been a long-standing goal for all inertial confinement fusion research.”

Several attempts to achieve the same energy yield as the August 2021 experiment did not succeed, but all of them reached higher energies than any previous experiments. The data gained from these and other experiments are providing crucial clues as to what went right and what changes are needed in order to achieve a sustained fusion reaction.

The technology is still in its infancy, of course. It will have to go through many design iterations before we will have a fusion reactor capable of sustained reaction, and then we have to figure out how to scale it all up to a useable level (a megajoule may sound like a lot, but it takes 3600 megajoules to equal just one megawatt hour of electricity. A typical nuclear plant outputs about 530 to 550 MW. You can see from that how far we have to go, but now we know for certain that nuclear science is on the right track.

Fusion power is a long dreamed-of achievement, and the concept has been part of the fabric of science fiction for nearly a hundred years. It has remained tantalizingly just out of reach, but now we know it can be done, because we’ve done it. A future powered by nuclear fusion is on its way.

Below is the NIF optic beam conditioning unit, that prepares the lasers before striking the target.