The US Department of Energy and the National Nuclear Security Administration announced on 13 December the achievement of fusion ignition at the Laurence Livermore National Laboratory, in what is considered a major scientific breakthrough, decades in the making. On 5 December a team at LLNL’s National Ignition Facility (NIF) conducted what is said to be the first controlled fusion experiment in history to reach this milestone, by briefly producing more energy from fusion than the laser energy used to drive it.

“This is a landmark achievement for the researchers and staff at the National Ignition Facility who have dedicated their careers to seeing fusion ignition become a reality, and this milestone will undoubtedly spark even more discovery,” said US secretary of Energy Jennifer M. Granholm.

LLNL’s experiment exceeded the fusion threshold by delivering 2.05 MJ of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a fundamental science basis for inertial fusion energy (IFE).

A long series of science and technology developments will still be needed to achieve affordable IFE at the scale needed to contribute to the national energy mix, and in recognition of this DOE is currently restarting a broad-based, co-ordinated IFE programme in the USA. Combined with private-sector investment, there is a great deal of momentum to drive rapid progress toward fusion commercialization.

In the 1960s, a group of pioneering scientists at LLNL hypothesised that lasers could be used to induce fusion in a laboratory setting. Led by physicist John Nuckolls, who later served as LLNL director from 1988 to 1994, this idea became ‘inertial confinement fusion’, kicking off more than 60 years of research and development in lasers, optics, diagnostics, target fabrication, computer modelling and simulation and experimental design.

To pursue this concept, LLNL built a series of increasingly powerful laser systems, leading to the creation of NIF, the world’s largest and most energetic laser system.