Scientists around the world have been trying for decades to recreate the unfathomable power of the sun here on Earth, and a group in China has outperformed our nearby star. Not for long, however. The group working the exploratory trial superconducting Tokamak (EAST) effectively warmed the reactor’s inside plasma to 100 million degrees Celsius (212 million Fahrenheit).
In the stars, hydrogen dissolves in helium, then in heavier elements. The melting process releases large amounts of energy and the by-products of the fusion are not radioactive. The only nuclear energy we have ever used on Earth is fission, which requires hazardous radioactive material and carries the risk of a reactor meltdown.
It is easy to understand why fusion is so interesting, but it is difficult to gather atoms in a reactor. Once the fission commences, it keeps on its own. Fusion requires a constant supply of energy because we do not have concentrated solar density to destroy atoms. The best way to do this is to do it with a tokamak-type reactor – that’s what EAST is. A tokamak heats hydrogen (usually an isotope of deuterium) at high temperatures until it becomes a plasma. The magnetic fields then tighten the plasma in the internal toroidal chamber of the reactor. Some molecules will merge and release energy. However, up to now, all Tokamak reactors have consumed more energy than they have created
The Hefei Physical Science Institutes of the Chinese Academy of Sciences activated the reactor in 2006 to conduct fusion experiments. In the latest experiment, researchers combined four different heating methods to reach 100 million degrees Celsius: lower hybrid wave heating, electron cyclotron heating, ion cyclotron resonance heating, and neutral ion heating. This allowed the fusion to start inside the reactor but, as usual, it did not produce net positive energy. The maximum temperature maintained for about 10 seconds.
This last EAST experiment was not only to beat the sun at its own game. The team used this experiment to study the behavior of the plasma at such temperatures. This could help improve the design of future reactors. An MIT team is building a tokamak reactor that it believes will generate energy in the next few years, but it will not reach the same astronomical temperatures as the EST reactor.
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