How The World’s Biggest Laser Smashed a Nuclear-Fusion Record
CALIFORNIA – Annie Kritcher, a physicist at NIF, led the experimental campaign that finally achieved ignition. ( Image : Nature.com)
Original source: nature, Spring 2024. Click here for the article link
The US National Ignition Facility is the only laboratory where a nuclear-fusion reaction has generated more energy than it consumed. Here’s how it achieved this historic milestone and sparked fresh interest in fusion energy – By Jeff Tollefson
The US National Ignition Facility is the only laboratory where a nuclear-fusion reaction has generated more energy than it consumed. Here’s how it achieved this historic milestone and sparked fresh interest in fusion energy. By Jeff Tollefson
The Sun shone brightly on Livermore, California, on 8 June 2011, when researchers charged up the world’s largest laser for its first major fusion experiment. It might have seemed like a good omen for the stadium-sized facility, which is a flagship project of the US nuclear weapons programme.
That day, the laser at the US National Ignition Facility (NIF) blasted a pea-sized target with a huge jolt of energy. It was an important first step, but the test ended with a brief flash and a fizzle. This result would become frustratingly familiar.
The US$3.5-billion facility was designed with a singular goal: to compress hydrogen isotopes into a white-hot core, where their nuclei would meld to create helium and enough surplus energy to drive a cascade of fusion reactions. Nobody had expected success straight away, but by June 2011 the researchers were already eight months into a two-year effort that was expected to achieve ‘ignition’: when an experiment generates more energy than the laser supplies. Those 2 years would drag into 12.
In December 2022, the laboratory finally reached its ignition goal as laid out by the US National Academy of Sciences 25 years earlier, and the researchers have since upped their game. NIF shattered records this February by producing double the amount of fusion energy that the laser provided (see ‘Steady progress’), and the facility confirmed its sixth successful ignition experiment this month.
Sources: O. A. Hurricane et al. (2024)/O. Hurricane/NIF
The success at NIF has opened up fresh avenues of research into nuclear weapons and buoyed the budding field of fusion energy: both governments and businesses are now pouring money into the idea that humans might one day generate a limitless source of clean energy to help solve the climate crisis. NIF is not designed to provide that energy. The facility instead serves as a proving ground for fusion research, as one of the only places where scientists can explore the fundamental physics that would underpin any fusion-energy future.
“There is really no better place to be,” says Annie Kritcher, a physicist at NIF who led the experimental campaign that finally achieved ignition.
NIF researchers had to solve a mountain of technical issues to achieve their goal. Over the years, they went back to the drawing board time and again, even as pressure mounted from critics over the facility’s mammoth price tag and limited results. Here is the inside story of how the laser team achieved success and is now pushing towards even greater fusion milestones.
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