Germany just switched on a revolutionary nuclear fusion machine .


You probably didn’t notice, but a few hours ago, the world took a huge step towards the goal of achieving clean, limitless energy through nuclear fusion.

Physicists in Germany announced that they’ve just fired up one of the world’s largest nuclear fusion machines for the first time – and it was successfully able to contain super-hot blobs of helium gas, otherwise known as plasma.

The 16-metre-wide machine is the Wendelstein 7-X (W7-X) and it’s a type of nuclear fusion device called a stellarator. Scientists have been talking about the enormous potential of stellarators for decades, but this is the first time a team has shown that it can produce and control plasma just as well as other fusion reactor designs.

On 10 December, the Max Planck Institute for Plasma Physics tweeted out thisincredible image of its new machine’s first plasma:

Nuclear fusion occurs when atoms fuse together at incredibly high temperatures and generate energy, and the reason scientists are so excited about it is because it has the potential to produce an almost-unlimited supply of energy from little more than salt water. This is the same process that’s fuelled our Sun for the past 4.5 billion years, and is predicted to continue doing so for another 4 billion years.

Unlike nuclear fission, which powers today’s nuclear power plants, nuclear fusion also doesn’t produce any radioactive waste, and is a whole lot safer.

But it’s also been incredibly tricky for scientists to achieve, because it requires them to construct a device that can produce and control a 100-million-degree-Celsius blob of plasma.

The key to controlling plasma is using superconducting magnets, and scientists have already built several working doughnut-shaped fusion reactors known astokamaks.

But there’s a big problem with tokamak reactors – they can only maintain plasma for a maximum of 6 minutes and 30 seconds at a time, which isn’t long enough to harvest significant energy. In other words, we’ve already been able to achieve nuclear fusion, but it consumed way more energy than it generated.

And this is why the launch of the stellarator is so exciting, because it’s predicted that the device will be able to control plasma for an unheard-of 30 minutes at a time.

In its first run, the machine was filled with helium – an unreactive gas – heated with a laser to around 1 million degrees Celsius. This plasma was maintained for around one-tenth of a second, which may not sound like much, but was enough to show the machine works.

“We’re very satisfied,” said Hans-Stephan Bosch, who led the team. “Everything went according to plan.”

The next step will be to increase the duration of helium plasma discharges, with the ultimate goal of building them up to 30 minutes in length. In January, the scientists will start trying to produce plasma from hydrogen, which is what would be used in a functioning nuclear fusion machine.

To be clear, the point of W7-X has never been to produce energy. This device is simply a proof-of-concept to show that the stellarator concept actually works. If all goes to plan, the things we learn from W7-X will help us build the next-generation of stellarators, which could quite literally change the world, and end our reliance on fossil fuels forever. Or as this commenter put it so perfectly on YouTube: “Help us Wendlestein 7-X, you’re our only hope.”

Skip forward to around the 23.30 mark of this live stream to see the scientists get super pumped when the machine produces plasma for the first time. What a time to be alive.

Germany’s about to switch on a revolutionary nuclear fusion machine


For more than 60 years, scientists have dreamed of a clean, inexhaustible energy source in the form of nuclear fusion. And they’re still dreaming.

But thanks to the efforts of the Max Planck Institute for Plasma Physics, experts hope that might soon change. Last year, after 1.1 million construction hours, the institute completed the world’s largest nuclear fusion machine of its kind, called a stellarator.

They call this 16-metre (52-foot) wide machine the W7-X. And following more than a year of tests, engineers are finally ready to fire up the US$1.1 billion machine for the first time, and it could happen before the end of this month,Science reported.

The black horse of nuclear reactors

Known in the plasma physics community as the ‘black horse’ of nuclear fusion reactors, stellarators are notoriously difficult to build. This video below demonstrates the construction of W7-X, which took 19 years to complete:

Between 2003 and 2007, as the project was being built, it suffered some major construction set backs — including one of its contracted manufacturers going out of business — that nearly cancelled the whole endeavour.

Only a handful of stellarators have ever been attempted, and even fewer have been completed.

By comparison, the more popular cousin to the stellarator, called a tokamak, is in wider use. There are over three dozen operational tokamaks across the globe, and more than 200 built throughout history. These machines are easier to construct and, in the past, have proven to do the job of a nuclear reactor better than the stellarator.

But tokamaks have a major flaw that W7-X is reportedly immune to, suggesting that Germany’s latest monster machine could be a game-changer.

How a nuclear reactor works

nuc-reacSchematic of the average tokamak. Notice how it has fewer layers than the stellarator and the shape of the magnetic coils is different. 

The key to a successful nuclear reactor of any kind is to generate, confine, and control a blob of super-heated matter, called a plasma — a gas that has reached temperatures of more than 100 million degrees Celsius (180 million degrees Fahrenheit).

At these blazing temperatures, the electrons are ripped from their atoms, forming what are called ions. Under these extreme conditions, the repulsive forces, which normally make ions bounce off each other like bumper cars, are overcome.

Consequently when the ions collide, they fuse together, generating energy in the process, and you have what is called nuclear fusion. This is the process that has been fuelling our sun for about 4.5 billion years and will continue to do so for another estimated 4 billion years.

Once engineers have heated the gas in the reactor to the right temperature, they use super-chilled magnetic coils to generate powerful magnetic fields that contain and control the plasma.

The W7-X, for example, houses 50 5.4-tonne magnetic coils, shown in purple in the GIF below. The plasma is contained within the red coil:

stellarator2

The difference between tokamaks and stellarators

For years, tokamaks have been considered the most promising machine for harnessing the power of the sun because the configuration of their magnetic coils contains a plasma that is better than that of currently operational stellarators.

But there’s a problem: Tokamaks can only control the plasma in short bursts that last for no more than 7 minutes. And the energy necessary to generate that plasma is more than the energy engineers get from these periodic bursts.

Tokamaks thus consume more energy than they produce, which is not what you want from nuclear fusion reactors, which have been touted as the “most important energy source over the next millennium.”

Because of the stellarators’ design, experts suspect it could sustain a plasma for at least 30 minutes at a time, which is significantly longer than any tokamak. The French tokamak “Tore Supra” holds the record: 6 minutes and 30 seconds.

If W7-X succeeds, it could completely turn the nuclear fusion community on its head and launch stellarators into the lime light.

“The world is waiting to see if we get the confinement time and then hold it for a long pulse,” David Gates, the head of stellarator physics at the Princeton Plasma Physics Laboratory, told Science.