A forest of tiny wires lets an ultrashort laser pulse reach deep into matter. The result: hundreds of times more fusion neutrons.

A forest of tiny wires lets an ultrashort laser pulse reach deep into matter. The result: hundreds of times more fusion neutrons.

AI-generated conceptual illustration. Structures and particle trails are not to scale.

Give light room to get in.

A flat surface absorbs the laser near its face. A nanowire array has open spaces, so the pulse can enter the target and heat a larger volume. The geometry changes what happens next.

The wires are made of a plastic rich in deuterium —a form of hydrogen whose nucleus has an extra neutron. Laser-heated electrons strip atoms apart, creating plasma: a mixture of electrons and charged nuclei.

The wires rapidly expand. Deuterium nuclei accelerate into the spaces between them. A small fraction collide hard enough to fuse. One possible fusion reaction releases a neutron, which scientists can detect outside the plasma.

A lifetime in 140 femtoseconds.

Choose a target. Then move through the pulse to see why gaps between wires matter—and why that advantage lasts only an instant.

Light finds a way in.

The pulse travels into the gaps between the nanowires, heating material beneath the surface.

Light enters the gaps

An explanatory animation, not a numerical simulation; sizes and particle counts are not to scale. Times follow the simulation snapshots in Figure 1, relative to the peak of a 60 fs pulse. Pulse width is measured at half its peak intensity (FWHM). As expanding plasma fills the gaps, it limits further penetration of the laser.

One change. 492 times the yield.

Under matched irradiation conditions, nanowire targets produced an average of 492 times as many neutrons as flat targets. Switch between the two to make that ratio visible.

Flat target · reference yield

Each lit dot represents one relative yield unit. This is a normalized comparison, not a count of individual neutrons.

Measured averages from 11 nanowire shots and 6 flat-target shots under the same irradiation conditions (Figure 4). Individual laser shots vary.

A 1.64-joule laser pulse produced 3.6 million neutrons—about 2.2 million neutrons per joule. This separate record is a neutron-production result, not a demonstration of net energy gain.

Let the neutrons tell the time.

Light arrives first. Neutrons follow. By measuring arrival times at different distances, researchers can estimate neutron speed—and therefore energy. Move the detector to try it.

Watch a neutron cross the gap.

Ideal flight times for a 2.45 MeV neutron moving at approximately 21.65 million metres per second; animation is slowed down. These calculations exclude instrument delays. The paper measured 2.48 ± 0.14 MeV (Figure 3), consistent with neutrons from the D–D reaction. One nanosecond (ns) is a billionth of a second.

A smaller route to intense neutron pulses.

This experiment shows how engineering a target at the nanoscale can improve a compact fusion neutron source. Such short neutron pulses could help probe materials and capture images of their internal structure. This study demonstrated source physics, not electricity generation.

Science, made explorable.

Based on A. Curtis et al., “Micro-scale fusion in dense relativistic nanowire array plasmas”, Nature Communications 9, 1077 (2018).

Source paper published under CC BY 4.0. Interactive diagrams are original explanatory models. Hero artwork is an AI-generated conceptual illustration. This is an independent educational companion.