Scientists around the world have been trying for decades to recreate the unfathomable power of the sun here on Earth, and a team in China has managed to best our local star. Not for very long, though. The team operating the Experimental Advanced Superconducting Tokamak (EAST) managed to heat the reactor’s internal plasma to 100 million degrees Celsius (212 million Fahrenheit). That’s six times hotter than the sun, but it doesn’t have any net power generation.
In stars, hydrogen fuses into helium, and eventually into heavier elements. The fusion process releases large amounts of energy, and the byproducts of fusion aren’t radioactive. The only nuclear power we’ve managed to utilize on Earth is fission, which requires dangerous radioactive materials and comes with the risk of a reactor meltdown.
It’s easy to see why there’s so much interest in fusion, but it’s hard to coax atoms together in a reactor. Once you get fission going, it’s self-sustaining. Fusion requires constant energy input because we don’t have the concentrated gravity of the sun to smash atoms together. The best way we’ve found to do it is with a tokamak-style reactor — that’s what EAST is. A tokamak heats hydrogen (usually a deuterium isotope) to high temperatures until it becomes plasma. Magnetic fields then squeeze the plasma together inside the reactor’s toroidal internal chamber. Some of the molecules will fuse and release energy. However, all tokamak reactors thus far have consumed more power than they created.
The internal chamber and magnets of EAST.
The Hefei Institutes of Physical Science of the Chinese Academy of Sciences activated the reactor in 2006 as a way to run fusion experiments. In the most recent experiment, researchers combined four different heating methods to reach 100 million Celsius: lower hybrid wave heating, electron cyclotron wave heating, ion cyclotron resonance heating, and neutral beam ion heating. This successfully kicked off fusion inside the reactor, but as usual, it didn’t produce net positive energy. The maximum temperature held for about 10 seconds.
This latest EAST experiment wasn’t just about beating the sun at its own game. The team used the high-temperature experiment to study the way plasma behaves at such high temperatures. That could help improve future reactor designs. A team at MIT is in the process of building a tokamak reactor that it claims will generate power in the next few years, but it won’t reach the same astronomical temperatures as the EAST reactor.
Now read: NASA-Funded Startup to Build Fusion-Powered Rockets, Huge German fusion reactor powers up, giving age-old tech a new shot, and Wednelstein 7-X stellerator generates plasma, proves its promise for fusion
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