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After thousands of nuclear fusion experiments, Chinese scientists
made a big breakthrough on May 28 in their quest to create an artificial
sun that could help solve the world's energy problems. They set a record for sustained heat in nuclear plasma－a temperature
of 120 million C for 101 seconds－said Gong Xianzu, a physicist in charge
of the experiment in Hefei, Anhui province. Gong, a leading researcher at the Institute of Plasma Physics in
Hefei, said on Tuesday that the result at the Experimental Advanced
Superconducting Tokamak, or EAST－nicknamed the "Chinese artificial
sun"－also reached a temperature of 160 million C for 20 seconds. A tokamak is a device that uses a powerful magnetic field to confine a
nuclear reaction. It is one of several types of magnetic confinement
devices being developed to produce controlled thermonuclear fusion
power. The technology is said to be the leading candidate for a
practical fusion reactor. "The experiments try to simulate the nuclear fusion reaction that
happens in the sun," said Gong, who joined the research 30 years ago. Although the temperature at the core of the sun is relatively
cool－about 15 million C－the density of plasma, which consists of ions
and free electrons, is high enough to generate a sustained reaction. In a fusion reaction, two or more atomic nuclei are combined to form
one or more different atomic nuclei and subatomic particles.
Theoretically, the process can produce massive amounts of clean, safe
energy that could be manipulated in a nuclear reactor. On Tuesday, scientists and engineers were continuing the experiment
for the 99,145th time using the doughnut-shaped tokamak－which has a
vacuum system, radio frequency wave system, laser scattering system and
microwave system－a technical introduction that was explained, after they
made the breakthrough at their 98,958th attempt on Friday. Gong said the ultimate goal of the team's research is to create the necessary conditions for a fusion reactor. "If we compare the tokamak facility to the engine of a car, then the
reactor is akin to the vehicle as a whole," he said, adding that a
vehicle is normally built for road tests before finally finding
commercial use. Ground was broken at the end of 2018 for construction of a fusion
reactor－known as the Comprehensive Research Facility for Fusion
Technology－in the outskirts of Hefei's Luyang district. The
infrastructure is nearly complete, according to recent media reports. The CRAFT website says construction will take five years and eight months. "Challenges in the ongoing research come from two areas," Gong said.
"We need to create the necessary conditions in which a fusion reaction
can occur and meanwhile overcome a lot of engineering difficulties to
make the reaction absolutely controllable." He said the test reactor, which is still in the initial design phase,
will use deuterium, a hydrogen isotope－a varied form of hydrogen with
twice its atomic mass－that is abundant in the sea, to provide a steady
stream of clean energy. "We estimate that the deuterium in 1 liter of seawater can pro-duce
through a fusion reaction the amount of energy produced by 300 liters of
gasoline," he said. Gong expressed hope that the reactor would be ready in the near
future so he can personally witness it playing a major role in
fulfilling China's commitment to achieving carbon neutrality before
2060. He said that in 2006 he witnessed the launch of the tokamak
facility in Hefei, which was the first of its kind. The fusion reactor will be an internationally open platform for
scientists from around the world, according to the CRAFT website.
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