Physics

Nanowire-zapping lasers unlock micro-scale nuclear fusion efficiency record

Nanowire-zapping lasers unlock...
The target chamber can be seen in the front of this image of the lab at CSU, while the high-powered laser lurks in the background
The target chamber can be seen in the front of this image of the lab at CSU, while the high-powered laser lurks in the background
View 2 Images
The top left image is a scanning electron microscope photo of the deuterated polyethylene nanowires; the other three images are computer simulations of those nanowires exploding after being struck with the laser blasts
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The top left image is a scanning electron microscope photo of the deuterated polyethylene nanowires; the other three images are computer simulations of those nanowires exploding after being struck with the laser blasts
The target chamber can be seen in the front of this image of the lab at CSU, while the high-powered laser lurks in the background
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The target chamber can be seen in the front of this image of the lab at CSU, while the high-powered laser lurks in the background

Researchers at Colorado State University (CSU) have broken the efficiency record for nuclear fusion on the micro-scale. Using an ultra-fast, high-powered tabletop laser, the team's results were about 500 times more efficient than previous experiments. The key to that success is the target material: instead of a flat piece of polymer, the researchers blasted arrays of nanowires to create incredibly hot, dense plasmas.

We have nuclear fusion to thank for our very existence – without it, the Sun wouldn't have fired up in the first place. Inside that inferno, hydrogen atoms are crushed and through a series of chain reactions, eventually form helium. In the process, tremendous amounts of energy are released. Theoretically, if we can harness that phenomenon we could produce an essentially unlimited supply of clean energy, and although breakthroughs have been made in recent years, nuclear fusion energy remains tantalizingly out of reach.

But the process could have other applications as well, which could be unlocked by getting it to work on a smaller scale. Rather than the huge laser setups used by other researchers to recreate the conditions at the center of stars, the CSU team used a relatively compact laser that could fit on a tabletop to beam ultra-fast pulses of light at the target.

The top left image is a scanning electron microscope photo of the deuterated polyethylene nanowires; the other three images are computer simulations of those nanowires exploding after being struck with the laser blasts
The top left image is a scanning electron microscope photo of the deuterated polyethylene nanowires; the other three images are computer simulations of those nanowires exploding after being struck with the laser blasts

In other experiments, that target is usually a flat piece of a material, but in this case, the researchers used arrays of nanowires made of deuterated polyethylene. The laser blasts destroy the nanowires in a matter of femtoseconds (quadrillionths of a second), creating ultra-high density plasmas, which in turn give off helium and a huge amount of neutrons.

The scientists report that their experiment produced up to 2 million fusion neutrons per joule of laser energy. That's about 500 times more than other experiments have produced using flat targets, and sets a new record yield for lasers of this intensity.

Along with improving our understanding of the mysterious interactions between light and matter, more efficient fusion neutron production could help advance neutron imaging techniques. These neutral subatomic particles are proving useful for peering inside objects in a similar way to X-rays, but they cause no damage to the target and can penetrate metals and other materials that X-rays can't.

The research was published in the journal Nature Communications.

Source: Colorado State University

7 comments
piperTom
The referenced " huge amount of neutrons" might be useful in some ways, but is also a huge problem. Neutrons create new isotopes in whatever they hit - most of that will be radioactive.
notarichman
you use kindling to start a fire easier. i wonder if the above practice could be used to start a bigger fire by using tiny jets of helium going into the array at the proper moment.
VincentWolf
Fusion for energy production is still hundreds of years off.
Douglas E Knapp
Vincentwolf, bet you are wrong. It is very human to think this way but it is shown over and over to be wrong. "When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong." Clarke Just saying your 100's years seems right then look at it as a doubling of tech ever 14 months. So we have 800,400,200, 100, 50, 25, 22(.5), 11, 5, 2, 1 so about 11 doubling or 11 years plus 10 years to implement, so we should have it in 21 years. Naturally calculated at 12 months so plus a bit more.
Mike Kling
Maybe Doc Brown's Mister Fusion is just around the corner.
BanisterJH
Commercial energy production via fusion is just 5 years away... - twenty times in a row, starting in 1950.
Kpar
"but they cause no damage to the target" Depends on the target, doesn't it? The whole idea of the "neutron bomb" (enhanced radiation weapon) was to kill people rapidly, while minimizing blast damage.