An artist’s rendering shows how the National Ignition Facility’s 192 beams enter an eraser-size cylinder of gold and heat it from the inside to pr

With explosive new result, laser-powered fusion effort nears ‘ignition’

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2021-08-18 01:30:06

An artist’s rendering shows how the National Ignition Facility’s 192 beams enter an eraser-size cylinder of gold and heat it from the inside to produce x-rays, which then implode the fuel capsule at its center to create fusion.

More than a decade ago, the world’s most energetic laser started to unleash its blasts on tiny capsules of hydrogen isotopes, with managers promising it would soon demonstrate a route to limitless fusion energy. Now, the National Ignition Facility (NIF) has taken a major leap toward that goal. Last week, a single laser shot sparked a fusion explosion from a peppercorn-size fuel capsule that produced eight times more energy than the facility had ever achieved: 1.35 megajoules (MJ)—roughly the kinetic energy of a car traveling at 160 kilometers per hour. That was also 70% of the energy of the laser pulse that triggered it, making it tantalizingly close to “ignition”: a fusion shot producing an excess of energy.

“After many years at 3% of ignition, this is superexciting,” says Mark Herrmann, head of the fusion program at Lawrence Livermore National Laboratory, which operates NIF.