German physicists got Nuclear Fusion reactor heated to nearly 54 million degrees Fahrenheit

We’re one step closer to a future of near-limitless clean energy. 

Physicists in Germany just found a way to minimize a major heat-loss problem plaguing a promising kind of nuclear fusion reactor called a “stellarator.”

The future of clean energy: Nuclear fusion occurs when the nuclei of two atoms merge into one. This releases an enormous amount of energy — it’s literally enough to power the sun and other stars.

If we could harness the power of nuclear fusion on Earth, it would be an absolute game changer in the battle against climate change.

Recreating fusion on Earth requires scientists to “put the sun in a box.”

Fusion doesn’t produce any carbon emissions (like the burning of fossil fuels) or long-lasting radioactive waste (like nuclear fission), and unlike solar and wind power, it isn’t dependent on the weather.

Designing a nuclear fusion reactor: Nuclear fusion can only happen under extreme heat and pressure — Nobel-winning physicist Pierre-Gilles de Gennes once said recreating it on Earth would require scientists to essentially put the “sun in a box.”

Scientists have designed a few different “boxes” — nuclear fusion reactors — that can create the conditions needed for fusion, but they require more energy than they produce, and until that changes, fusion won’t be a viable source of power.

Stellarators 101: A stellarator is a type of nuclear fusion reactor that looks like a massive donut that has been squished and twisted out of shape. A coil of magnets surrounds the stellarator, creating magnetic fields that control the flow of plasma within it.

By subjecting this plasma to extreme temperatures and pressure, a stellarator can force atoms within it to undergo fusion,  and compared to other fusion reactors, stellarators require less power and have more design flexibility.   

However, the device’s design makes it easier for the plasma to lose heat through a process called “neoclassical transport” — and without heat, you can’t have sustained fusion.

“It’s really exciting news for fusion that this design has been successful.”

NOVIMIR PABLANT

What’s new? Now, researchers have reduced heat loss in the world’s largest and most advanced stellarator — called the Wendelstein 7-X — by optimizing its magnetic coil.

In doing so, they were able to heat the interior of their nuclear fusion reactor to nearly 54 million degrees Fahrenheit — that’s more than twice as hot as the sun’s core — and testing confirmed that their design had specifically minimized heat loss due to neoclassical transport. 

“It’s really exciting news for fusion that this design has been successful,” physicist Novimir Pablant said. “It clearly shows that this kind of optimization can be done.”

And now, stellarators are one step closer to being a usable design for a nuclear fusion reactor.

A big problem with fusion is solved leading us near to a perpetual energy source

As the dynamics inside a fusion reactor are very complex, the walls melt.

Image credit: Max Planck Institute of Plasma physics. Cutaway of a Fusion Reactor

A team of researchers from the Max Planck Institute for Plasma Physics (IPP) and the Vienna University of Technology (TU Wein) have discovered a way to control Type-I ELM plasma instabilities, that melt the walls of fusion devices. The study is published in the journal Physical Review Letters.

There is no doubt that the day will come when fusion power plants can provide sustainable energy and solve our persistent energy problems. It is the main reason why so many scientists around the world are working on this power source. Power generation in this way actually mimics the sun.

For the method to work, the plasmas must be heated to 100 million degrees Celsius inside the reactors. A Magnetic fields surrounds the plasma keep the walls of the reactor from melting. The shell that forms around the plasma can  work only because the outermost few centimeters of the edge of that shell, called the magnetically formed plasma edge, is very  well insulated.

However, there is a drawback to this method of keeping the plasma's solar-level heat within. In that edge region, which are plasma instabilities, exist there (ELMs). ELMs typically happen during fusion reactions. In the course of an ELM, intense plasma particles may strike the reactor's wall and cause possible damage.

The researchers returned to a technique of operation that had been previously abandoned, in a move that would remind anybody of presenting an original of anything after numerous trials of other approaches just to discover that the original is the correct one.

Instead of possibly harming the reactor's walls, very destructive instabilities. Numerous minor instabilities are possible, but none of them pose a threat to the walls of the reactor.

Elisabeth Wolfrum, research group head at IPP in Garching, Germany, and professor at TU Wien, states that "Our discovery marks a breakthrough in understanding the occurrence and prevention of massive Type I ELMs." The operating regime we provide is most likely the most optimistic case for fusion power plant plasmas in the future. Now, the findings have been released in the publication Physical Review Letters.

Toroidal tokamak fusion reactor is the name of the reactor. Extremely hot plasma particles travel quickly within this reactor. Strong magnetic coils make sure that the particles stay contained rather than destroying the reactor's walls by striking them.

How a fusion reactor works is complex, and the dynamics inside are also complex. The motion of the particles depends on the plasma density, temperature and magnetic field. The reactor's operation is determined by the selection of these parameters. When the smaller particles of plasma strike the walls or the reactor, instead of a round shape, the reactor takes on a triangular shape with rounded corners, however this shape is far less damaged than that caused by a big ELM. 

The primary author of the study, Georg Harrer, compares it to a cooking pot with a cover where water is beginning to boil. "If the pressure increases more, the lid will raise and shake violently as the steam escapes. However, if you tilt the lid just a little bit, steam may constantly escape while the top stays put and doesn't rattle."

The possibility for a continuous fusion process with enormous energy is greatly increased by this. A perpetual energy source.

Reference(s): Physical Review Letters