Scientists at the National Ignition Facility in California pointed their 192 beam laser at a cylinder containing a tiny diamond fuel capsule at 1:03am on Monday, 5 December.
The sun is powered by fusion reactions, which were sparked by the intense laser beam burst. Fusion reactions produce extremely high temperatures and pressures.
Such experiments had previously been conducted at the National Ignition Facility (NIF), a division of Lawrence Livermore National Laboratory, but this time the energy produced by the reaction was greater than the laser power used to initiate it.
The hope is to one day construct power plants that use a fusion reaction to generate copious amounts of carbon-free electricity. Scientists have been working for decades to reach that threshold.
That still seems far away. The technology still needs to be developed extensively in the interim.
A peppercorn-sized synthetic diamond capsule that holds the fuel is one of the crucial parts of NIF. A successful fusion experiment depends on the characteristics of that spherical capsule.
Any imperfections could sabotage the reaction, so the sphere must be flawlessly clean and free of contaminants.
But those expertly crafted spheres are not produced in California. They are the outcome of many years of labor by Freiburg, Germany-based Diamond Materials.
According to Christoph Wild, who serves as managing director of Diamond Materials alongside Eckhard Wörner, "the demands on the [spherical] capsules are very high.".
We work closely with Lawrence Livermore and make every effort to eliminate flaws like impurities, cavities, and uneven walls. ".
Chemical vapour deposition is the method used by Diamond Materials' 25-person staff to create synthetic diamond.
Each batch of 20 to 40 capsules takes about two months to make by painstakingly layering tiny diamond crystals around a silicon carbide core and repeatedly polishing.
They discovered during the development process that even the most meticulous polishing was insufficient because the surface was still pitted and uneven at the microscopic level.
They eventually learned, in collaboration with LLNL teams, that they could glaze a polished capsule with a brand-new layer of diamond crystals to produce the precise mirror-like finish they required.
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The silicon core of the diamond capsules is taken out at LLNL, where the hollow sphere is then filled with deuterium and tritium, two heavy forms of hydrogen that power the fusion reaction.
According to Mike Farrell, vice president of inertial fusion technology at General Atomics, which is LLNL's largest industrial partner, "around that fuel pellet is a cylinder made of gold and depleted uranium.".
An aluminum cylinder, the capsule's third and last layer, is used to cool down its contents prior to the reaction.
Optics, which includes anything that facilitates the transmission, detection, or use of light, is another crucial area of technology for NIF.
NIF uses a lot of that technology to power the most potent laser in the world, and every time the machine is turned on, optical components suffer damage.
In order to perfect and supply replacement parts, as well as debris and blast shields, NIF has been working closely with optics manufacturers like Zygo Corporation and specialized glassmaker SCHOTT since the early 1970s.
The next task for NIF and its partners will be to further advance technology in order to replicate and enhance the reaction after December's successful experiment.
Mike Farrell hopes that the development will encourage support for additional study. The research altered scientific thinking. It was always believed that ignition would be almost impossible to achieve and might not materialize for 40 years. The outcome in December was startling. ".
Diamond Materials hopes to be able to devote more time to research once it is back in Freiburg. About 20% of our team is engaged in research, and both of us, the managing directors, are physicists, according to Mr. Wild.
We need to prioritize production over research because it consumes a lot of resources at the level we produce. As a result, the team will likely continue to expand. After all, today's research produces tomorrow's products. ".
Teams from all over the world are utilizing a variety of strategies in their race to construct a functional fusion power plant. However, it will take a lot of time and billions of dollars in funding.
According to Mr. Farrell, the NIF milestone from last year will likely boost the industry: "Now that ignition has been shown to be feasible, government and corporate funding may be easier to come by. ".
Finding materials that can withstand the high energy released by the fusion process is just one of the many engineering challenges that must be overcome in order to build a functioning power plant.
But Mr. Farrell is quick to note how quickly development can pick up steam following the initial breakthrough.
"Engineers take over after you demonstrate first principles, as we have just done, to determine how to accomplish that in a repeatable manner.
"Keep in mind that the first flight by the Wright brothers took place in 1903, while the first supersonic flight occurred in the 1950s. Things can change a lot in 40 years or so.
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