China’s Artificial Sun

  China's Artificial Sun Generated a Magnetic Field : Clearing a Real Path for Fusion

China’s large Huanliu-3 nuclear fusion reactor follows decades of research in Chengdu. The world’s dozens of active tokamak experiments share ideas, scientists and more. This tokamak, like many others, contributes to International Thermonuclear Experimental Reactor (ITER). China’s quest to harness nuclear fusion as a clean and abundant energy source took a significant step forward with the recent breakthrough of its artificial sun generating a magnetic field. This achievement is a major milestone in the field of fusion research, paving the way for further advancements and eventual commercialization of fusion power. It’s a crucial step forward in the quest for clean energy. China joined the quest for an enormous, internationally cooperative nuclear fusion reactor in 2023. Now, they’ve reached a milestone by generating its magnetic field for the first time, a field that is entirely new in tis design. The “artificial sun” reactor, Huanliu-3 (HL-3), is a tokamak run by 17 collaborating labs and facilities around the world. But the much-ballyhooed quest to make energy using these huge reactors still has a decade or more to go, with a lot of misinformation in the mix.

While HL-3 puts China in the group of forerunners in nuclear fusion research, this reactor isn’t the largest (by far), and this milestone is only for its own timeline. This reactor is not close to operating consistently or producing energy that compares to the vast amounts of energy it and other similar reactors, known as tokamaks, require to operate. But HL-3, like many global tokamaks, is considered a proving ground for technologies which nations like China will offer to the truly world-leading ITER project in France. In that sense, each nation’s developments could make a difference going forward.

The “artificial sun,” officially known as the Experimental Advanced Superconducting Tokamak (EAST), successfully generated a magnetic field of 100 teslas for 1,000 seconds. This is a remarkable feat as it surpasses the previous record of 25 teslas set by the German Wendelstein 7-X fusion device. The magnetic field is crucial in confining and controlling the super-hot plasma necessary for nuclear fusion, making it a key component in achieving sustained fusion reactions. A tokamak is a donut-shaped (toroidal, in the science parlance) container that holds a stream of superheated magnetic plasma and is reinforced by massive magnets and super cooling encasement. The plasma, a cohesive “cloud” of atoms under star-like conditions, ends up hosting the same reactions that fuel the actual stars. The nuclei of atoms fuse together and release an enormous amount of energy... in theory. We know it happens in the stars, but we’ve never seen it happen in the same runaway, self-sustaining manner inside a thousand-ton piece of machinery on Earth.

In order to sustain fusion reactions, extreme temperature and pressure conditions are required. The EAST device is able to create these conditions by heating the plasma to over 100 million degrees Celsius, which is six times hotter than the core of the sun. Additionally, the plasma is held in place by the intense magnetic field, preventing it from coming into contact with the walls of the tokamak and causing damage. So, what does it mean for a world-class “artificial sun” tokamak reactor like HL-3 to establish its own, novel magnetic field design? Well, it’s a huge milestone within the field of tokamak research, as the magnetic field is what actually contains the superheated, fusion-generating plasma. Because plasma reaches a million degrees, it can’t make contact with any other material, or it will both instantly cool down out of the energy range and damage or destroy the part it touches. As such, a successful magnetic field is the only thing that will ever allow a tokamak to contain the plasma and keep it hot enough to make net energy.

Fusion energy has long been touted as a potential solution to the world’s energy needs due to its abundance, cleanliness and safety. Unlike nuclear fission, which produces radioactive waste and carries the risk of catastrophic meltdowns, fusion reactions produce minimal radioactive waste and pose no risk of a runaway reaction. Additionally, fusion fuel sources such as deuterium and tritium are abundant and can be extracted from seawater, ensuring a virtually limitless supply of fuel. There are a number of structural issues with how today’s tokamaks build their magnetic fields. The extremely huge electromagnets used in these machines are key to tokamaks’ designs (ITER received the most powerful magnet ever made in 2021), and they're under development all the time. But they all create hotspots that interrupt the plasma like an island in a stream, either because they are discretely installed at intervals around the shell of the tokamak, or simply because they’re made (by humans) of the naturally occurring materials we have on Earth. In the cosmos, stars are not contained, so this never comes up. But in a generator, it's yet another hurdle to overcome. All this means that a new configuration for a magnetic field can be a huge step forward, especially for HL-3, which is considered a feeder technology for ITER. Chinese media reports that China has signed on to build a vacuum chamber module for ITER. The vacuum vessel is essential to ITER’s goals, because it helps make the experiment plausibly safe to do, to contain a starlike reaction along the French waterfront.

Despite the recent achievements in fusion research, there are still significant challenges to overcome before fusion power can be commercially viable. These challenges include sustaining fusion reactions for extended periods of time, managing the heat and radiation produced during the process, and developing materials which can withstand the extreme conditions inside a fusion reactor. However, with continued research and investment, scientists are optimistic about the future of fusion energy and its potential to revolutionize the way we produce electricity. The language barrier and state-owned media both make it difficult to scrutinize Chinese projects like HL-3, and there aren’t a lot of meaningful comparisons between the world’s dozens of active projects in existence. China has another active nuclear fusion reactor in the international eye (Experimental Advanced Superconducting Tokamak, or EAST), which has been iterated upon China’s Hefei Institutes of Physical Science since the 2000s.

HL-3, however, comes from a lineage at Southwestern Institute of Physics in Chengdu, 900 miles west on the cusp of vast Western China. This program dates back decades as well, and both have steadily grown more and more powerful over decades of huge upgrades and rebuilds. HL-3 improves on previous designs, and is likely to get a larger machine with a larger overall amount of power going. We still have never reached the threshold where a nuclear fusion reactor makes more energy than it uses, and to be honest, it’s not clear that we definitely will. But each step forward in proven tokamak technology brings the possibility of nuclear fusion energy closer to reality. And when we’re so many steps away, every little bit counts."  

China’s successful generation of a magnetic field in its artificial sun marks a significant advancement in the pursuit of fusion energy. The ability to confine and control super-hot plasma is a crucial step towards achieving sustained fusion reactions and ultimately harnessing the power of the sun as a clean and abundant energy source. While there are still challenges to overcome, the progress made in fusion research brings us closer to a future where fusion power could meet the world’s energy needs in a safe and sustainable manner.