Fusion experiment generates 1.3 megajoules of energy and breaks a record

An experiment with inertial confinement nuclear fusion, conducted from the facilities of the National Ignition Facility (NIF), in the United States, made it possible to produce a record energy explosion of more than ten quadrillion watts. To achieve such a result, the researchers shot a tiny sphere of hydrogen with the world’s largest lasers.

A new record

Inside a giant building at the National Ignition Facility (NIF), affiliated with Lawrence Livermore National Laboratory (LLNL), in California, is an array of 192 lasers — the most powerful in the world — that can be combined to produce 1.9 megajoules of ultraviolet energy in a centrally located room. These pulses last only a billionth of a second, but focused on a small target, they can generate enormous temperatures and pressures that could revolutionize the world in the future.

Physicists at LLNL recently aimed 192 giant lasers at a pea-sized hydrogen pellet, resulting in the release of 1.3 megajoules of energy in 100 trillion seconds. That’s about 10% of the energy from sunlight hitting the Earth at any given time, and about 70% of the energy the grain had absorbed by the lasers. The previous record was 170 kilojoules of energy produced. Researchers hope one day the break-even point – or “ignition” – from the pellet, where it Release 100% or more energy than she absorbs.

“This result is a historic step forward for fusion inertial confinement research and opens a fundamentally new regime for the exploration and advancement of our critical national security missions”said Kim Budil, director of the Lawrence Livermore National Laboratory.

Indeed, the researchers hope that this new milestone can expand their capabilities in the field of nuclear fusion weapons, the NIF’s main mission. However, these advances could also lead to new ways of harnessing the energy of nuclear fusion that powers the stars, promising to release colossal amounts of “clean” and nearly “unlimited” energy.

laser nuclear fusion
A colorized image from a 2016 experiment at the National Ignition facility. Credit: Don Jedlovec

star energy

Modern nuclear power plants use nuclear fission, which generates energy by splitting heavy nuclei of elements into lighter nuclei. Conversely, stars generate energy by linking lighter nuclei together to make heavier elements. These objects can fuse many different elements together, but the combination of hydrogen in helium is the one that produces the most energy.

Most attempts to reproduce this stellar process on Earth — in China, Korea or even France — are based on giant donut-shaped reactors called “tokamaks.” Inside, the intent is to heat deuterium and tritium to over 100 million degrees Celsius until a plasma cloud forms. This cloud must then be controlled with ultra-strong magnets long enough to fuse the deuterium and tritium atoms and release energy.

In contrast, the method proposed by the Lawrence Livermore National Laboratory is one of the few ways to achieve nuclear fusion without using a tokamak. Instead, the NFI uses a series of laser light amplifiers the size of three football fields to focus laser beams on hydrogen pellets in a spherical metal “target chamber” 10 meters wide.

As it stands, this configuration cannot be used in a fusion power plant. Indeed, these lasers can only fire once a day, while a power plant would have to vaporize several fuel pellets every second. On the other hand, efforts will be made in the future to adapt the process in such a way that it can be used commercially.