NIF’s Fusion Ignition Shot a ‘Hot Topic’ at SPIE Photonics West

A standing-room-only crowd at the recent SPIE Photonics West convention listened raptly to a presentation about LLNL’s long road to fusion ignition on Dec. 5, 2022. That road was paved by six decades of laser research coupled with key upgrades made in recent years to NIF’s complex laser system, target fabrication, diagnostics, and experimental designs.

And the journey has just begun, NIF Chief Engineer for Laser Systems Jean-Michel Di Nicola told the audience.

“The major accomplishment—and the highlight—was December 5th, which is truly not the finish line, but rather opening a door in exploring a new era in this field of physics,” Di Nicola said during his plenary address at the international optics and photonics community convention held at San Francisco’s Moscone Center.

“Ignition strengthens our national security and provides us fresh impetus with the scientific foundation for inertial fusion energy,” he added. “This is the next grand challenge. And it’s going to take the efforts and involvement of the community with a partnership that is synergistic for our (stockpile) stewardship mission.”

Di Nicola was invited to deliver one of the plenary addresses on Jan. 30, capping a line of speakers presenting “hot topics” at the Photonics West LASE conference, which focuses on industrial lasers, laser sources, and laser applications. Hundreds of attendees packed the room, some standing two-deep in the back of the meeting hall.

Interest in NIF’s scientific achievement has been sky-high since the Dec. 5 inertial confinement fusion experiment that produced 3.15 megajoules (million joules, or MJ) of fusion energy output. That was 1.5 times more energy than the ultraviolet laser energy delivered to the target, exceeding the definition of ignition used by the National Academy of Sciences in 1997.

Di Nicola—who is also NIF’s acting co-program director for Laser S&T and Systems Engineering—was among several LLNL speakers at the convention, which drew more than 22,000 attendees from 85 countries and featured 1,400 exhibitors and 4,500 technical presentations during its Jan. 28 to Feb. 2 run. The convention marked the return of the annual meeting’s first full in-person gathering since the COVID-19 pandemic began.

For the historic shot, NIF delivered 2.05 MJ of ultraviolet energy to the tiny target capsule containing hydrogen fuel, compared to 1.8 MJ for the Aug. 8, 2021, experiment that brought NIF about 70 percent of the way to ignition.

Di Nicola noted NIF was able to increase the laser drive by 8 percent, from 1.9 MJ to 2.05 MJ for the Dec. 5 experiment. That was due to improvements made to the NIF laser system by the optics materials and fabrication, laser systems engineering, and operations teams.

“All these improvements in terms of target quality, laser drive, laser accuracy, diagnostics capabilities, (and) design of the experiments, made the difference” in achieving ignition, Di Nicola said. “The good news is NIF has not yet reached its full potential. Next summer, we’ll be deploying new capability with better precision.”

NIF plans to deliver about 2.2 MJ, or 8 percent more energy, later this year. “And then we’ll be embarking on the rest of the journey trying to go into the tens of megajoules of yield, and we expect that to be in the 2023-2028 timeframe,” he said. “And laser energy could potentially be also increased from the 2.6-megajoule to the 3-megajoule range” after the completion of NIF sustainment and upgrade projects now underway.

Di Nicola thanked the many vendors and industry partners who have contributed to the quest for ignition and who were also at the conference. “We want to acknowledge them, especially at the Photonics West venue, as well as collaborators from different countries across the world,” he said.

Di Nicola also presented an invited paper, “Recent laser performance improvements and latest results at the National Ignition Facility,” which was co-authored by 55 LLNL colleagues.

And he was interviewed during the conference for Photonics Media’s “All Things Photonics” podcast:

Talks by other LLNL speakers at the convention included:

• “Experimental operations at the National Ignition Facility,” by Steven Weaver.

• “Freeform crystal optics for arbitrary space-variant polarization control in large aperture, high energy lasers,” by Anthony Vella.

• “Beam-line parameter image processing optimization and maintenance for beam alignment in the National Ignition Facility,” by Abdul Awwal.

• “Four-dimensional multi-level stimulated rotational Raman scattering dynamics in air,” by Samuel McLaren.

• “High energy operation of a diode-pumped Tm:YLF laser,” by Issa Tamer.

• “High repetition rate, high energy petawatt laser for the matter in extreme conditions upgrade,” by Brendan Reagan.

• “Probing the physics of metal 3D printing: Past, present, and future,” by Manyalibo Matthews.

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