Scientists use a laser fusion reactor to create fuel particles in an instant

As the question of how to make a laser fusion reactor practical looms large, scientists at the University of Rochester's Laser Energexics Laboratory (LLE) have come up with a way for fusion lasers to essentially make their own fuel pellets.

In December 2022, scientists at the National Ignition Facility at Lawrence Livermore National Laboratory in California made a breakthrough, an experimental reactor that took six years to develop, using an array of 192 high-energy lasers, focused on a single point, to hit a small ball. Deuterium and tritium trigger the first inertial fusion ignition reaction.

Although this has scientists and engineers opening metaphors and opening some real champagne corks, practical fusion reactors are still a long way off. However, that hasn't stopped the Rochester team, led by LLE senior scientist Igor Igumenshchev and LLE Theory Department director Valeri Goncharov, from working out the logistics of how to take laser fusion out of the lab and into the real world. The real world.

One of the bigger hurdles is how to make the fuel pellets needed to run the reactor. Currently, the manufacturing process for such particles is complex and expensive, and involves using liquid helium to freeze deuterium and tritium - radioactive isotopes of hydrogen - to a temperature of just 11 Kelvin above absolute zero, then placing them in layers to form particles.

That may be fine for lab experiments that don't need to worry about balancing the books, but a working fusion reactor will need about a million of these fuel pellets per day. So the Rochester team is developing an idea, first proposed in 2020, to create a technology that would allow lasers in a reactor to generate their own fuel sheets in a laser explosion before imploding and igniting.

Instead of using solid particles, the scientists injected deuterium and tritium into foam capsules. The trick is that when the laser array is fired at the capsule, the beam causes the capsule to collapse into a sphere with the same density as the deuterium tritium liquid fuel, which then implodes.

For now, the process is just a scaled-down proof-of-concept using LLE's OMEGA laser. However, the team claims that future lasers with longer, higher-energy pulses should be able to ignite new capsules.

"Combining this target concept with the highly efficient laser systems currently being developed at LLE would provide a very attractive path for fusion energy," said Igumenshchev.

The research is in the journal Physical Review Letters.

Source: Laser Network