The preamplifiers of the National Ignition Facility are the first step in increasing the energy of laser beams as they make their way toward the target chamber. NIF recently achieved a 500 terawatt shot—then it had to turn it down. (credit: Lawrence Livermore National Laboratory )

In order to investigate something called inertial confinement fusion (or ICF, which we’ll talk about below), scientists at the National Ignition Facility built the biggest damn laser in the world. Located in Livermore, California, the NIF’s laser is capable of producing something like 500TW of power per pulse, and the facility is so futuristic that parts of Star Trek Into Darkness were filmed there.

So imagine the disappointment felt by everyone at the NIF when, even though their laser worked fine, the amount of fusion it appeared to produce was shockingly low. Researchers now may have identified the problem and have shown that many neutrons can be observed at the NIF. Neutrons are a result of fusion, so the number of neutrons is a measure of how many atoms have fused. The problem is that, to produce efficient fusion, we can’t currently use the facility at its full power.

Small hydrogen bombs

The idea behind inertial confinement fusion is simple. To get two atoms to fuse together, you need to bring their nuclei into contact with each other. Both nuclei are positively charged, so they repel each other, which means that force is needed to convince two hydrogen nuclei to touch. In a hydrogen bomb, force is generated when a small fission bomb explodes, compressing a core of hydrogen. This fuses to create heavier elements, releasing a huge amount of energy.