Nuclear fusion breakthrough will be tested with the world's largest laser

The breakthrough happened in an incredibly small slice of time, less than it takes for a beam of light to travel an inch. In this little moment, nuclear fusion as a source of energy gone from a distant dream to reality. The world is now grappling with the implications of this historic step.

For Arthur Pak and the countless other scientists who have spent decades making it this far, the work is just the beginning. Pak and his colleagues at Lawrence Livermore National Laboratory now face a daunting task: to start over, but better and bigger.

That means perfecting the use of the world’s largest laser, housed in the National Ignition Facility in the lab that sci-fi fans will recognize from the movie. “Star Trek: Into Darkness” when used as a set for the Starship Enterprise’s warp core.

Just after 1am on December 1st. 5, the laser fired 192 beams in three carefully modulated pulses onto a cylinder containing a tiny diamond capsule filled with hydrogen, with the aim of triggering the first fusion reaction which produced more energy than was needed. took to create. He succeeded, paving the way towards what scientists hope will one day be a new carbon-free energy source that will allow humans to harness the same energy source that lights up the stars.

Pak, who joined the Lawrence Livermore lab outside San Francisco in 2010, woke up at 3 a.m. that day, unable to stop himself from checking early results from his home in San Jose. He had tried to stay awake for the shot himself, eventually giving up as the painstaking preparations for the experiment dragged on late into the night. “If you stayed awake every time, every time for 10 years, you would go crazy,” he said.

Over the past few months, it was clear his team was closing in, and in the pre-dawn darkness he checked a key number that could show if they had succeeded – a number of neutrons produced by the explosion.

“When I saw that number, I was blown away,” he said.

You can work your whole career and never see this moment. You do it because you believe in the destination and love the challenge,” said Pak, experience diagnostics manager. “When humans come together and work collectively, we can do amazing things.”

The team at Lawrence Livermore – a government-funded research lab – will likely perform its next test in February, with several more experiments to come in the months following. The goal will be to continue to increase the amount of energy produced in the reaction. That means more tinkering: using more laser energy. Adjust the laser beam. Generate more X-rays into the target – a key step in the process – using the same amount of energy. Perhaps, eventually, to upgrade the facility itself, a move that would require Department of Energy buy-in and huge funding.

All of this will take years, if not decades, starting with small experiments in the Lawrence Livermore lab that only last a few nanoseconds.

We need to understand: Can we simplify things? Can we make this process easier and more repeatable? Can we start doing it more than once a day? said Kim Budil, director of the Lawrence Livermore laboratory. “Each of them is an incredible scientific and technical challenge for us.”

Most experts predict that the world is still at least 20 to 30 years away from fusion technology becoming viable at a scale large enough and affordable enough to produce commercial energy. This timeline puts fusion beyond the scope of meaningful use to achieve global net-zero emissions goals by 2050. In this sense, fusion could be the carbon-free energy source of the future, but not of the current global energy transition facing .continuing obstacles.

Fusion has captured the scientific imagination for decades. It is already being used to give modern nuclear weapons their devastating power, but the dream is to tame it for civilian energy demand. If this could be scaled, it would lead to power plants that provide abundant electricity day and night without emitting greenhouse gases. And unlike today’s nuclear power, triggered by a process called fission, it wouldn’t create long-lived radioactive waste. Whole generations of scientists have pursued him. President Joe Biden’s chief science adviser, Arati Prabhakar, spent a summer working on the lab’s laser fusion program as a 19-year-old student at Bell Bottoms – in 1978.

“It’s a tremendous example of what perseverance can accomplish,” she said at a news conference last week. “That’s how you do really big, hard things.”

Fusion of atoms

The successful laser shot produced fusion reactions generating 3.15 megajoules of power, exceeding the 2.05 megajoules transmitted by the laser. It was a major threshold, the first time that more energy had come out of the laser than it had entered. But the equation has to lean much more in the direction of what comes out to become commercially viable.

While today’s nuclear power plants use fission, splitting atoms apart, fusion fuses atoms together. Fusion researchers have followed two main leads. Lawrence Livermore, using a process called inertial confinement, blasts targets with laser beams, imploding a small amount of hydrogen until it fuses into helium. A commercial plant using this approach would have to repeat the process over and over again, extremely quickly, to generate enough energy to feed the electrical grid.

Many companies develop inertial trust systems, although there are significant differences. Some are investigating different materials for the target, while others use particle accelerators instead of lasers, triggering the fusion reaction by slamming atoms together.

The main competing idea is called magnetic confinement, with systems that create a cloud of plasma, superheated to hundreds of millions of degrees, which can trigger a fusion reaction. Powerful magnets control the plasma and keep the reaction going. This approach has yet to achieve a net energy gain, and the approach faces challenges including developing better magnets and creating materials that can withstand very hot temperatures and be used for the container to hold the plasma.

To date, about $5 billion in funding has flowed to fusion companies, with the vast majority going to magnetic confinement technologies, according to trade group Fusion Industry Association.

Inertial confidence might be better suited to prove that fusion can work, said Adam Stein, director of nuclear energy innovation at the Breakthrough Institute, a research group based in Oakland, Calif. But in the longer term, when it comes to commercialization, “plasma magnetic confinement is more likely to be successful,” he said.

“Be optimistic”

Years have been spent refining every part of the process at the Lawrence Livermore lab.

Much of the success is down to precision. Fuel capsules all contain tiny imperfections that can make a significant difference in the course of the reaction. So does the frozen hydrogen inside, a mixture of deuterium and tritium isotopes. The team would often produce hydrogen ice, melt it, and retry several times before a shot, hoping to get the best possible target and increase the chance of success.

Anyone working on fusion “should be optimistic,” said Denise Hinkel, a physicist who focuses on improving the predictive ability of the program’s computer simulations and who has worked at Lawerence Livermore for 30 years. “Otherwise you wouldn’t stay on the pitch.”

By this summer, the giant laser will be able to deliver around 8% more energy than it did in this month’s firing, according to Jean-Michel Di Nicola, chief engineer of the laser from the National Ignition Facility. Target manufacturing program manager Michael Stadermann said the lab is also developing a computer program that can examine fuel capsule shells for flaws much faster than humans. They are also working with the capsule manufacturer to improve the manufacturing process.

Lawrence Livermore’s breakthrough may remain only a moment in scientific history and not mark the start of a new fusion industry powering the world. Bridging the gap between experimentation and commercialization could take decades, if at all. And magnetic confinement may eventually be the winning fusion method, providing the world with abundantly clean energy. Pak, a soft-spoken man with a tuft of brown hair and a quick wit, said the result would not disappoint him.

“They can learn from us – we can learn from them,” said Pak, 40. “When I’m an old man, I’ll be really happy with my contributions.”

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