China says it has performed a key test of a nuclear fusion machine it is developing, reaching temperatures about seven times that of the Sun’s interior.
The test took place at the Experimental Advanced Superconducting Tokamak (EAST) at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences (CASHIPS). The machine reached temperatures of more than 100 million °C (180 million °F), the temperature at which nuclear fusion takes place.
EAST is a tokamak reactor, which is shaped like a donut and uses large currents to twist the plasma inside, confining it using magnetic fields. Another type of reactor, called a stellerator, is shaped like a twisted donut to twist the magnetic fields.
In the past few years, a number of experimental fusion reactors have successfully sustained a plasma for a minute or so. China’s test is particularly significant though for the temperatures it achieved. The interior of our Sun reaches temperatures of “just” 15 million °C (27 million °F). But to kickstart nuclear fusion in a reactor on Earth, temperatures about seven times higher are required.
“If we can achieve that, the payoff would be massive,” ScienceAlert noted. “Unlike nuclear fission – where surplus energy comes from the decay of large atoms into smaller elements – nuclear fusion doesn't result in anywhere near as much radioactive waste. In fact, the end result of squeezing together isotopes of hydrogen is mostly helium.”
China had previously set a world record of sustaining a plasma of 101.2 seconds last year, and has now turned its attention to raising the temperature inside the machine. The ultimate goal will be to sustain this plasma indefinitely, providing a clean and practically endless source of power.
China is part of an international collaboration known as ITER (International Thermonuclear Experimental Reactor), along with 34 other countries, to develop an operational fusion reactor. The experiments at EAST go some ways to make that dream a reality.
“EAST, a device independently designed and developed by Chinese scientists to harness the energy of nuclear fusion, is taking a step closer to maintaining a more stable fusion reaction as long as possible and at an even higher temperature,” the Chinese state-owned CGTN news network said.