China's 'Artificial Sun' Smashes Nuclear Fusion Record

China's "artificial sun" has reached a new milestone in the rapidly advancing field of nuclear fusion. On April 12, a superhot fusion plasma was generated, sustained and confined for 403 seconds, bringing commercial-scale fusion energy one step closer to reality, national media reported.

Nuclear fusion creates energy in the same way as our sun. The process involves the smashing together of two atoms with such force that they combine into a single, larger atom, releasing huge amounts of energy in the process.

Unlike nuclear fission—the nuclear reaction that is currently used in the energy sector—fusion does not create radioactive waste. It produces three to four times more energy than fission and does not release carbon dioxide into the atmosphere, unlike burning fossil fuels. Fusion is also a very fragile process that will shut down in a fraction of a second if the correct conditions are not maintained. Therefore, there is no risk of nuclear meltdown from this reaction.

However, there is one problem: fusion requires vast amounts of energy to achieve the required temperature and pressure for the reaction to take place. As a result, scientists have not yet managed to get significantly more energy out of a fusion reaction than they put in.

Researchers around the world are working to overcome these challenges, increasing the efficiency of the process on multiple fronts to bring the dream of clean, almost limitless fusion energy to life.

China's "artificial sun," officially known as the Experimental Advanced Superconducting Tokamak (EAST), does this by containing the reaction in an enormous, donut-shaped contraption called a tokamak.

A tokamak is a donut-shaped contraption that uses powerful magnets to contain a circular flow of super-hot plasma. Plasma—sometimes referred to as the fourth state of matter—is created when atoms are heated to such high temperatures that they are torn apart, resulting in a soup of negatively charged electrons and positively charged ions.

These positively charged ions will usually repel each other but, in the sun, a high pressure is created by its intense gravitational forces that thrust the ions together and overcome this repulsion. However, on Earth it is nearly impossible to replicate this, so the plasma must be heated even more, to temperatures roughly six times hotter than the center of the sun or more.

To maintain these superhot temperatures, the plasma must be contained in a small area, which is where the magnets come in. "Essentially, you've got a system of very large magnets," Tony Langtry, head of engineering at U.K.-based fusion company Tokamak Energy, previously told Newsweek. "The field needed to control the plasma is generated by passing huge currents through some big conductors.

"As the current goes through these conductors they generate magnetic fields, and since the plasma also has a current, it reacts to, and can be controlled by, these fields."

In the past, metals like copper were used to create these magnets. However, when a current is passed through these conventional materials, their structure will resist the flow of electricity, meaning that some of the energy put in will be wasted.

One of the features that allows EAST to reach and maintain high temperatures efficiently is its use of superconducting magnets. Superconductors are materials that produce zero resistance and no waste heat under the right conditions.

Companies like Tokamak Energy are working to develop the next generation of superconductors that work even more efficiently at these higher temperatures.

While EAST—which is located at the Institute of Plasma Physics, under the Chinese Academy of Sciences in Hefei—has previously sustained a plasma for a longer period, the recent record of 403 seconds is significant because of the state in which these particles were kept.

Song Yuntao, the director of the Chinese Academy of Science's Institute of Plasma Physics, said that the plasma had been sustained in a "high-confinement" mode, which supports a higher temperature and particle density and lays the foundation for more efficient power generation.

This achievement breaks the reactor's previous record for steady-state high confinement plasma, which was set in 2017 at 101 seconds.

Describing the success, Tokamak Energy's co-founder and executive vice chairman, David Kingham, told Newsweek: "This is another significant achievement in fusion, made possible using superconducting magnets. Long pulse durations with short intervals between pulses are needed for sustained high power output in fusion power plants."

According to Tim Bestwick, the chief technology officer for the U.K. Atomic Energy Authority, extending the time for a sustained and controlled plasma like this involves three things: "Having machines that can run for extended periods; being able to deliver sustained heating power into the plasma; and being able to monitor and control the plasma."

EAST began operations in 2006 and has contributed to the 35-year collaboration between China, the EU, India, Japan, South Korea, Russia, the U.K. and the U.S. to develop and optimize the world's largest tokamak machine, ITER, which is currently under construction in France. ITER is expected to produce its first plasma at the end of 2025, with full-scale operations beginning in 2035.

"China has an active fusion program, and is extensively involved in the highly collaborative international ITER program," Bestwick told Newsweek. "This result demonstrates welcome progress in the field."