Energy

High-powered laser closes in on nuclear fusion ignition

High-powered laser closes in o...
A colorized image of a 2016 experiment at the National Ignition facility
A colorized image of a 2016 experiment at the National Ignition facility
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A colorized image of a 2016 experiment at the National Ignition facility
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A colorized image of a 2016 experiment at the National Ignition facility

The field of nuclear fusion has seen some exciting advances of late, with scientists demonstrating how fuels can be heated to the temperatures needed for the necessary reactions to take place. All are working towards a version of the technology where the energy generated through these reactions is enough to keep the sequence going, something known as fusion ignition, and something that could fulfill fusion's promise of unlimited, clean energy. "Extraordinary results" from experiments with an extraordinarily high-powered laser have just taken us a whole lot closer to that goal.

Inside a 10-story building the size of three football fields at Lawrence Livermore National Laboratory’s National Ignition Facility in California is an array of 192 lasers, which can combine to deliver 1.9 megajoules of ultraviolet leaser energy onto a tiny chamber in the center. These pulses take place in a billionth of a second, but concentrated onto something the size of BB projectile, they can create tremendous temperatures and pressures that might just kickstart an energy revolution.

Like all nuclear fusion experiments, the idea is to recreate the reactions that take place constantly within our Sun, where extreme temperature and pressure combine to force the fusion of separate atoms into helium, which releases momentous amounts of energy as a result. The approach being pursued at the National Ignition Facility is known as inertial confinement fusion, and since coming online in 2009, we've seen its scientists take some important steps forward.

This began with hitting a target with a one-megajoule laser and demonstrating control over the scattering beams in 2010, and then delivering a record-setting 500-trillion-watt laser shot in 2012. A big breakthrough came in 2014, when the NIF team demonstrated a one-off "fuel gain," where the lasers were focused onto a tiny plastic capsule filled with deuterium and tritium, creating a reaction that gave off more energy than what was put in.

This was an important milestone in the pursuit of ignition, where the fusion reactions would create a plasma hot enough to trigger a runaway effect in which reactions take place over and over in a self-sustaining cycle. As reported by Science magazine, the NIF team have since proceeded to experiments yielding 100 kJ, and one even as high as 170 kJ, edging ever so closer to their goal.

The scientists are now claiming a massive leap forward, with experiments conducted in early August achieving a yield of more than 1.3 megajoules. The work is yet to be peer-reviewed, a process that will help them work through the technical reasons behind this huge success, but the initial analysis points to an eight-fold improvement on their most recent round of experiments, and one that moves them much closer to the goal of fusion ignition.

At this stage, the team points to design improvements in the casing that holds the fuel capsule, better precision of the laser and tweaks that drive up the energy coupled with the reactions, as the reasons for the gains. Plans for the next experiments are already in the pipeline, and are expected to take place in the coming months.

Source: Lawrence Livermore National Laboratory

8 comments
8 comments
Bob Stuart
Fusion is certainly a neat trick, but as a power source, it is still dependent on deuterium or tritium, and so it produces nasty nuclear waste for all our descendants to caretake. I don't think there is any reason to pursue this, with renewables so cheap now.
michael_dowling
UN scientists have declared code red for humanity,and fusion is one thing that can be put on the back burner while we concentrate on slashing CO2 emissions, and expanding the use of renewables at an increased rate.
paul314
So they've got 1.9 megajoules of UV going in to get 1.3 megajoules of (not necessarily easy to collect) energy coming out. And (depending on the efficiency of the UV laser system) that could be anywhere up to 100 megajoules going in to create the laser pulse. Hmm.

ICF was originally developed as a modeling tool for designers of new hydrogen bombs, and it doesn't really seem to have progressed that far beyond its origins.
guzmanchinky
It's exciting to see progress in this field, renewables can only take us so far, to really power massive desalinization and CO2 removal plants we need much more power...
Food4Thought
A nifty little trick...maybe to better understand the reaction, etc. I don't see this approach as viable for supporting power generation however. I can only imagine how hard it would be to repeat this every second or few seconds, harvest energy, etc... As I understand it, one can create fusion in a hydrogen bomb, but it is not very useful for creating a power source. Nonetheless, an interesting experiment.
fasteddie2020
Fusion Power is the answer!!! But not with lasers and Tokamaks. Here is the answer:

https://uploads.disquscdn.com/images/09597b104b84e91f1e31dae27c07cefbb9984224ce373d4fe4c98b503d0669c9.jpg

Why do I have to do all the thinking, while scientists waste billions into more fusion experiments.
madsci
Bob Stuart, as I understand a closed loop nuclear fusion power plant would produce helium and tritium. As you mention tritium is used as a fuel so would be ultimately consumed. Could you enlighten me on the nasty nuclear waste problem by telling me what the waste is?
Christian Lassen
Why all the naysayers? Progress is awesome. Solar is 100x worse for the environment than Nuclear watt-for-watt, so lets not keep chasing that pipe dream. Wind is...inconsistent and expensive. Water has it's inherent limits, since only so much of it falls from the sky into places we can build dams. But nuclear: with modern recycling and waste refinement, now there's promise. I sat in a college engineering lecture in the early 2000's, the speaker was overseeing the building of the nuclear waste tunnels in Nevada and how at current rates they would be filled before they were even finished. Now I live in an area with lots of Nuclear Engineers and several nuclear research labs. Friends who work there say that refinement and recycling has gotten so good that we are pulling waste OUT of the tunnels to use over again and they will NEVER be filled.

I'm all for nuclear, and I'm all for research on fusion. Keep it going