China's Artificial Sun Breaks Record by Hitting 120 Million F in Race for Nuclear Fusion

Researchers bringing the nuclear process that powers the stars down to Earth to supply humanity's growing power needs have broken an important record in the generation of superheated plasma.

The team at China's "artificial sun" fusion facility—the Experimental Advanced Superconducting Tokamak (EAST)—have said that on December 30, 2021, they were able to generate 120 million degrees Fahrenheit plasma (around 70 million degrees Celsius) and hold it for 1,056 seconds.

Over its 15 years of operation, EAST—operated by the Chinese Academy of Sciences (ASIPP)—has achieved both these temperatures and this containment time before, but never in conjunction making this an important fusion milestone.

Gong Xianzu, a researcher at the ASIPP, said: "We achieved a plasma temperature of 120 million degrees Celsius (216 F) for 101 seconds in an experiment in the first half of 2021. This time, steady-state plasma operation was sustained for 1,056 seconds at a temperature close to 70 million degrees Celsius, laying a solid scientific and experimental foundation toward the running of a fusion reactor."

Tokamaks, like the donut-shaped EAST reactor, are often referred to as "artificial suns" as they are devices that replicate the fusion processes that occur within stars. These processes deliver the energy radiated by these stellar bodies, and researchers here on Earth aim to deliver this energy in a controlled manner to power our homes and cities.

Should scientists succeed in bringing this process down to Earth, fusion power could provide the world with a safe, sustainable, environmentally responsible, and abundant source of energy that is an alternative to fission nuclear power.

The fusion process is almost the opposite of the fission process that powers the current generation of nuclear power plants in that, rather than splitting atoms of heavy elements apart, it forces together atoms of light elements to create heavier atoms.

In the super-hot plasma—a gas of ionized atoms—that makes up stars, intense gravitational pressure forces the atoms of hydrogen together at high speeds to form helium.

A single helium atom doesn't have as much mass as two hydrogen atoms and this difference in mass is released as energy that is radiated away by stars.

To replicate this stellar process, tokamaks must heat heavy hydrogen atoms (deuterium and tritium) with lasers to temperatures up to hundreds of millions of degrees Fahrenheit while confining this plasma within powerful magnetic fields.

The temperature of the plasma in tokamaks needs to be hotter than that of stars, where fusion processes occur at about 60 million F. This is because Earth-bound scientists can't replicate the intense pressure generated by gravity at the heart of a star.

That means compensating by heating plasma to around least 270 million F, the temperature at which atomic nuclei in a tokamak will smash together rapidly enough to kick-start nuclear fusion.

Additionally, to actually generate usable fusion energy, tokamaks must contain the plasma they generate and maintain it at these temperatures long enough for atomic nuclei to begin smashing together and for the process to be self-sustaining.

Researchers working at EAST say they are working towards this goal, as are scientists at other tokamaks like the Korea Institute of Fusion Energy's Korea Superconducting Tokamak Advanced Research (KSTAR) reactor.

KSTAR set a world record in 2016 by maintaining a super-heated ionic gas of 90 million F for 70 seconds. EAST broke this record the following year by sustaining a 90 million F plasma for 102 seconds.

In 2021, EAST further topped this record by maintaining plasma at around 216 million F for about 101 seconds. This new development breaks the record for holding super-heated plasmas by maintaining a plasma for over ten times as long, albeit at a lower temperature.

Fusion is considered to be a cleaner process than fusion because it creates no radioactive waste, with the end-product of the fusion process being helium. Also, the fuel it consumes is light and abundant materials like deuterium, rather than expensive, rare, and dangerous elements, such as uranium or plutonium used in fusion plants.

Theoretically, these fuels can be obtained in large volumes from seawater, with one liter of water estimated by some experts to be sufficient to provide enough raw fusion material to produce the energy equivalent to the combustion of 300 liters of oil.

EAST Sun
(Left) China's donut shaped EAST tokamak reactor. (Left) A stunning image of the sun captured by NASA. Institute of Plasma Physics/ Chinese Academy of Sciences/NASA