Breaking the world record! China's "artificial sun" has achieved a major breakthrough!

The "artificial sun", also known as the "tokamak" device, is a nuclear fusion research device controlled by humans and created by simulating a series of reactions that occur in the sun during its luminescence and heat generation process. It is one of the future application directions of controlled nuclear fusion technology.

The "artificial sun" is not only clean and efficient, but can also stop the reaction spontaneously immediately when an accident occurs, because the conditions required to maintain the reaction are very harsh.

But making the fusion reaction stable is a challenge, which places high demands on plasma control technology. Recently, Chinese scientists have taken a small step towards overcoming this challenge.

The “high-constraint model” of the Institute of Western Physics

The Southwest Institute of Physics of China National Nuclear Corporation ("SWIP") announced that on August 25, the "China Loop 3" tokamak device (HL-2M) achieved high confinement mode operation under a plasma current of 1 million amperes for the first time.

This breakthrough is a reflection of the comprehensive capabilities of the nuclear fusion device and an important milestone in my country's nuclear fusion energy development process. Earlier in November 2022, the Institute of Nuclear and Astronomy announced that the HL-2M plasma current exceeded 1 million amperes for the first time. What is the significance of the "high confinement mode operation" achieved this time?

High confinement mode is an advanced reactor operation mode first proposed by German scientist Friedrich Wagner in 1982.

Compared with some earlier operating modes, the high confinement mode can greatly increase the density and energy storage of plasma in the process of heating plasma to achieve fusion conditions, and increase the efficiency of fusion reactions several times. The most direct impact of the discovery of the high confinement mode is that it can reduce the scale of fusion reactors and save construction costs. This is also the standard operating mode selected by the International Thermonuclear Experimental Reactor (ITER) under construction.

ITER under construction (photographed in 2018)

Image source: wikipedia

Future nuclear fusion reactors need to operate stably in high confinement mode at currents of millions of amperes. Specifically, to realize the application of nuclear fusion reactions, the energy produced by the reaction must be greater than the energy consumed, and there must be enough energy to maintain the reaction stable. These criteria are called the "Lawson criterion."

The success of this experiment means that they are one step closer to passing the Lawson criterion. To achieve this achievement, "(the research team) has overcome three key technical difficulties this year, including high confinement mode operation control under high current, high power heating system injection coupling, and advanced divertor configuration control," said Li Bo, associate researcher and director of the Control and Information Technology Research Laboratory of the Institute of Nuclear and New Energy Physics, in an interview with Xinhua News Agency.

Future Research Directions

The Institute of Physics of the West China University of Political Science and Law plans to further improve the parameters in the high confinement mode, such as raising the plasma temperature to 100 million degrees Celsius. In the future, HL-2M will also increase the plasma current capacity to more than 2.5 million amperes.

Actual footage of HL-2M 1 million ampere plasma operation

Image source: Xinhuanet

The Lawson criterion mainly depends on three core parameters: the ion temperature of the fuel, the plasma density and the energy confinement time.

Scientists are trying to improve these indicators one by one, and are getting closer to the goal of achieving controlled nuclear fusion applications. In terms of operating time, the "Eastern Super Ring" fully superconducting tokamak nuclear fusion experimental device (EAST) set a world record in April this year, successfully achieving steady-state high confinement mode plasma operation for 403 seconds.

In human history, nuclear fusion research has gone through more than a hundred years. In the past 20 years, with the completion of large-scale experimental devices such as HL-2M, scientists are constantly striving for new goals and are committed to realizing energy utilization by 2050.

References

[1] Xinhuanet. Visiting the new generation of artificial sun "China Circulation 3" [EB/OL]. http://www.news.cn/tech/20230901/f90cd937d9984314b9baa4c8221db374/c.html. 2023-09-01/2023-09-06.

[2] Dong Jiaqi. Tokamak high confinement operation mode and magnetic confinement controlled nuclear fusion[J]. Physics, 2010, 39(06): 400-405.

[3] Duan Xuru. Science and Technology Daily. Improving the triple product to make controlled nuclear fusion a reality [EB/OL]. http://www.news.cn/science/2022-11/08/c_1310674449.htm.2022-11-08/2023-09-06.

[4] China National Nuclear Corporation. Major breakthrough! my country has mastered advanced control technology for controlled nuclear fusion with high confinement [EB/OL]. https://www.cnnc.com.cn/cnnc/xwzx65/ttyw01/1365133/index.html.2023-08-28/2023-09-06.

Planning and production

Source: "Voice of Science and Technology Association" WeChat public account

Author: Qi Yiyin, a popular science writer

Editor: Jin Yufen