On May 28, the Experimental Advanced Superconducting Tokamak (EAST), known as the “artificial sun”, operating at the Institute of Materials Science in Hefei (Chinese Academy of Sciences), achieved the new limit of the planet reaching the highest temperature ever recorded.
It reached one hundred and twenty million degrees Celsius, for one minute and 51 seconds. EAST also managed to maintain a temperature of 160 million degrees Celsius for 20 seconds. This is a higher peak than that of the sun's core, which can reach a limit of 15 million degrees Celsius.
A tokamak (Russian: toroidal'naja kamera s magnitnymi katushkami: Russian acronym for "toroidal chamber with magnetic coils") is a device which uses a powerful magnetic field to confine plasma in the shape of a torus. Torus is a ring-shaped device in which a hot, rarefied gas (usually hydrogen, in the plasma state) is kept cohesive and away from inner walls by a magnetic field created by electromagnets outside the chamber. It was originally conceptualized and invented in the 1950s by Soviet professor Sadyk Azimovič Azimov (1914-88) and others at the Kurčatov Institute in Moscow.
China's experimental nuclear fusion device was created in 1998 and was called HT-7U at the time. With a view to making it easier to pronounce and remember, as well as having a precise scientific meaning for national and foreign experts, HT-7U was officially renamed EAST in October 2003.
In 2006, the EAST project was completed in a definitive and higher quality manner. In September-October 2006 and in January-February 2007, the EAST device performed two discharge debugs and successfully achieved stable, repetitive and controllable high-temperature plasmas with various magnetic configurations.
EAST has a nuclear fusion reaction mechanism similar to that of the sun. Its operating principle is to add a small amount of the hydrogen isotope deuterium or tritium to the device's vacuum chamber and generate plasma through a transformer-like principle, then increase its density and temperature to cause a fusion reaction - a process that generates enormous energy.
Over the ten years since its construction, EAST has continually made progress in the search for controllable nuclear fusion.
In 2009, the first round of EAST tests was successful, thus putting China at the forefront of nuclear fusion research. In February 2016, EAST's physics tests made another major breakthrough, achieving the longest temperature duration reaching 50 million degrees. In 2018, EAST reached a number of important milestones including 100 million degrees.
This means that mankind has made another major advance in its efforts to turn nuclear fusion into new, clean and inexhaustible energy.
Energy is the fundamental driving force behind the functioning of every aspect of life. The energy used today has many shortcomings and cannot fully meet human needs, while nuclear fusion energy is considered the ideal energy par excellence.
According to calculations, the deuterium contained in one liter of seawater can produce the equivalent of the energy of 300 liters of petrol, released after the nuclear fusion reaction, besides the fact that the product is not harmful. Although it is not a “perpetual motion machine”, nuclear fusion can provide energy for a long time. Not only can Marvel's hero Iron Man rely on the small reactor in his chest, but also raw materials can be obtained from seawater at an extremely low cost.
The first condition for nuclear fusion is to keep fuel in the fourth state of matter, after solid, liquid and gas - i.e. the plasma state.
When the plasma temperature reaches tens of millions of degrees Celsius or even hundreds of millions of degrees, the atomic nucleus can overcome the repulsive force to carry out the polymerisation reaction. Coupled with sufficient density and a sufficiently long thermal energy confinement time, the nuclear fusion reaction is able to continue steadily.
Nevertheless, it is particularly difficult to achieve both the temperature of hundreds of millions of degrees Celsius and the long-term confinement control of plasma stability.
While recognizing that nuclear fusion is the ultimate goal for solving the problem of mankind's future energy, there is both cooperation and competition in international research.
A sign of cooperation is that on July 28, 2020, a ceremony was held in France to launch the major project to install the International Thermonuclear Experimental Reactor (ITER). The ITER project is jointly implemented by China, the Republic of Korea (South Korea), Japan, India, Russia, the European Union and the United States.
On December 28, 2020, Seoul's Korea Superconducting Tokamak Advanced Research (KSTAR) set a new world limit at the time and its ionomer maintained a temperature of over 100 million degrees for 20 seconds.
In early 2018, the Plasma Science and Fusion Center at the Massachusetts Institute of Technology had begun designing and building a Soonest/Smallest Private-Funded Affordable Robust Compact fusion reactor more advanced than ITER, with a volume tens of times smaller and significantly reduced in cost. But it remains to be seen whether this goal can be achieved.
Chinese researchers have now achieved significant progress in this field and taken another important step towards obtaining energy from nuclear fusion.
In the future, if the production capacity and energy supply of the "artificial sun" is achieved, it will be another technological revolution that can promote social progress even more than the industrial revolution which, in fact, meant the beginning of pollution for the planet and exploitation by capital.
Although there is still a long way to go before the construction of the naval port on Jupiter described by the Chinese writer, Liu Cixin, in his novel The Three-Body Problem (San Ti), mankind is indeed advancing on the road to controllable nuclear fusion.
Nuclear fusion energy has exceptional advantages in producing rich resources, as well as no carbon emissions, so it is clean and safe. It is one of the ideal energy sources for mankind in the future, and can contribute significantly to achieve the goal of eliminating said carbon.
The two greatest difficulties in generating energy from nuclear fusion lie in regularly reaching hundreds of millions of degrees, and in stable ignition and control of long-term confinement.
For the time being, multiple extreme conditions are highly integrated and organically combined at the same time, but this is very difficult and challenging.
In hitting the record, it is the first time that the EAST device has adopted key technologies such as the first water-cooled all-metal active wall, as well as the high-performance tungsten deflector and high-power wave heating states.
At present, there are over 200 core technologies and nearly 2,000 patents on EAST, bringing together cutting-edge technologies such as 'ultra-high temperature', 'ultra-low temperature', 'ultra-high vacuum', 'ultra-strong magnetic field' and 'ultra-high current'.
The total power is 34 megawatts, which is equivalent to about 68,000 domestic microwave ovens heating up together. For 100 million degrees Celsius and -269 °C to coexist, it is necessary to use “ultra-high vacuum” with an intensity of about one hundredth of a billionth of the surface atmospheric pressure suitable for insulation. With a view to supporting this complex extreme system, almost a million parts and components work together on EAST.
The new EAST record further demonstrates the feasibility of nuclear fusion energy and also lays the physical and engineering foundations for marketing.
Energy on earth, stored in the form of fossil fuels, wind, water or animals and plants, originally comes from the sun. For example, fossil fuels evolved from animals and plants millions of years ago, and their energy ultimately comes from solar energy stored by the photosynthesis of plants at the base of the food chain. Therefore, regardless of the type of energy used by humans, they ultimately use the sun energy that comes from nuclear fusion.
If mankind could master the method for releasing the nuclear fusion energy in an orderly manner, it would be equivalent to controlling the sun energy source. Therefore, this is the reason why the controllable nuclear fusion reactor is called the "artificial sun".
Professor Valori is President of the International World Group