Researchers at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory are harnessing the power of computers to enhance the performance of fusion devices known as stellarators.
Inside a large, ring-shaped device, plasma, reaching temperatures many times hotter than the surface of the sun, swirls in powerful, controlled motion. From the outside, the machine resembles a metal ring encased in scaffolding and walkways. But within, it’s recreating the extreme conditions necessary for nuclear fusion—the same process that powers the sun and all other stars.
Researchers supported by the U.S. Department of Energy’s (DOE) Office of Science are working to deepen our understanding of fusion with the long-term goal of developing it into a viable commercial energy source. Scientists at the DOE’s Princeton Plasma Physics Laboratory (PPPL) have recently made significant progress in advancing stellarators, a promising type of fusion device known for its stability in confining plasma.
Fusion has the potential to provide a clean, virtually limitless source of energy. Unlike fossil fuels, it produces no greenhouse gases and generates no long-lived radioactive waste. Fusion works by heating light atomic nuclei, like those of hydrogen, until they form a plasma, a superheated, electrically charged gas. Since stars are made of plasma, it accounts for about 99% of the visible universe.
The key challenge is controlling this plasma. To make fusion energy practical, scientists must develop devices capable of sustaining a stable fusion reaction, one that produces more energy than it consumes, by effectively containing and managing the high-temperature plasma.
Magnetic Confinement Devices: Tokamaks and Stellarators
Fusion researchers are pursuing several different technologies, including magnetic confinement and inertial confinement. Two of the most common magnetic confinement configurations are tokamaks and stellarators. They both use very strong magnetic fields to confine the plasma and hold it in a donut shape.
One way that they differ is by the way the two produce those magnetic fields. Tokamaks have three large sets of magnetic field coils. One of them produces an electric current that runs through the center of the plasma. That electric current produces a magnetic field that boosts how well the plasma is confined. In contrast, stellarators have many magnet coils that loop around the outside of the plasma. They form twisting magnetic fields that wrap around the donut, without the need for a central current.
Stellarators have some major advantages over tokamaks. They need less power to sustain the fusion reaction, the design is more flexible, and they are less likely to have disruptions in the plasma that damage the device’s walls.
However, stellarators have one major issue – they can’t hold in the plasma’s heat as well as tokamaks. In particular, stellarators struggle to confine the most energetic particles in the plasma. Many of these are the particles that must be confined to sustain the fusion reaction. In addition, the more energetic particles are lost, the more likely they could damage the device’s walls. Because tokamaks’ symmetrical shape around an axis confines particles easily, they don’t have this problem. Scientists need to fix this fundamental issue before stellarators can be a viable design option.
A New Approach to Plasma Confinement
Fortunately, researchers at PPPL have found a few ways to address this problem. They know that certain configurations of the magnetic field lead to the trapped particles acting in ways that help confinement.
Now, scientists need to know how to adjust the magnets to produce magnetic fields in the right shape. In theory, the best solution would be to simulate how every particle moves in every magnetic field. However, that would take near-infinite amounts of computing power and time. It’s just not practical.
Instead, PPPL researchers partnering with scientists from Auburn University, the Max Planck Institute for Plasma Physics in Germany, and the University of Wisconsin-Madison applied an alternative method that uses a lot less computing power. Rather than predicting how each particle moves, they developed an easy-to-compute proxy function that predicts how fast the particles move away from the magnetic fields. This number has a consistent relationship with how well the magnetic fields are confining the plasma. Using this proxy function, the team was able to develop a number of different possible plasma configurations that would lose fewer energetic particles.
Although other scientists had used this technique before, they had never applied it to this specific type of stellarator. The project used code that was developed at DOE’s Oak Ridge National Laboratory and PPPL.
While these configurations aren’t designs for a specific device, they will help scientists move forward, knowing what paths to pursue. Using this method could help advance stellarator research. Eventually, it could enable stellarators to be a viable option for commercial fusion power.
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9 Comments
70 years later – and about 40 yeas past the projected date – there is no Terrestrial Fusion power. None.
Continued research should be very measured, and Terrestrial Fusion researchers should NOT be allowed to suggest it will arrive soon, causing too many to want to delay more fission power in hopes that Terrestrial Fusion is “just around the corner”. Terrestrial Fusion is far, far into the future….if ever.
However, Natural Fusion is here and ready to be exploited.
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Fusion power has been hyped forever. Get back to us when there is an functioning reactor that produces electricity rather that puff pieces.
With a attitude like that, there will NEVER be a functioning reactor. Investors and supporters (like Congress) have to believe that the problems are solvable. Fusion is nothing like the Manhattan Program where the US provided the brightest minds in the world and followed two separate tracks (U-235 and Pu-239), with significant amounts of money to fund the development. Up until now, the research has been slow and measured because, unlike during WWII, time is not of the essence. There are alternatives to fusion. Even at the present slow rate of progress, the problems will probably be solved well before fossil fuels become too expensive to use as an energy source.
The early time-estimates were overly optimistic because we knew so little about the details of controlled nuclear fusion that we didn’t know what we didn’t know. There have been some recent breakthroughs in the time of confinement and the amount of power produced that suggest we are actually getting close to solving the problem before civilization becomes limited by expensive and unreliable energy sources.
Naysayers aren’t the ones who make it across the finish line. They just make excuses.
Look at the coral castle the rudimentary generator i believe thats what it is sacred geometry
Look at the coral castle the rudimentary generator i believe thats what it is sacred geometry he said he had figured out how the pyramids were built . The man moved blocks of coral all by himself weighing a ton or more each to Construct this monument for his wife and he only worked at night.
Something I’ve never seen discussed, and I’m wondering if any readers here can provide insight, are the magnetic fields going to be strong enough to potentially disrupt migration paths of birds? If so, cost estimates should include magnetic shielding.
There already is a giant fusion reactor in the sky.
The title of the article implicitly acknowledges that with its reference to a star in a bottle. However, what the article is about is CONTROLLED thermonuclear fusion, specifically Stellarators and Tokamaks. Our sun is anything but under our direct control.
Myself I would like the fusion industry to be successful any idea can help if it is viable , that’s why I read about science , have always been a tinkerer . They have two different systems to work with , each has potential . Several mechanisms to control the surge bursts to level the plasma and a few are left , accomplishing the goal of stabilization . I would like to add a thought , would the earth’s magnetic field be involved with the geometry of the reactor donut that is built perpendicular to the wave of the field that surrounds the planet , the sun’s plasma is held together by magnetic fields , we live on a planet within a spheres magnetic field surrounding the planet , all the instruments connected to the reactor system are grounded to the earth may bring some kind of inclusion to the reactors operation . The earth spins and the field is generated evenly until the side of the earth rotates to face the sun then the field is acted upon with the radioactive winds of the sun’s rays .