China is making progress on its “artificial sun project” to develop a near-infinite source of energy. Chinese scientists working on this project have discovered a previously unknown mode of plasma activity that could enable more reliable and efficient nuclear fusion power production.
A discovery and demonstration of a new plasma operation scenario called Super I-Mode has been made on the Experimental Advanced Superconducting Tokamak (EAST), according to the Hefei Institutes of Physical Science, Chinese Academy of Sciences (CAS).
Hefei’s EAST reactor discovered “Super I mode” for the first time in December 2021 after a record 17-minute operation, SCMP reported. The findings, rigorously peer-reviewed, were published on January 6, 2023, in the international journal Science Advances.
The new high-limiting and self-organizing Super I mode exemplifies the advancement and reliability of the apparatus and provides information on how to maintain constant plasma operation for a long period of time.
The record-breaking excursion, which used magnetic fields to heat a plasma-laden gas composed of free-moving electrons and hydrogen ions to a temperature of 70 million degrees Celsius, managed to contain high energy both at the edge of the plasma and further into the plasma. .
Subsequent tests showed that the new module has high potential for use in the International Thermonuclear Experimental Reactor (ITER), according to researchers from the Chinese Academy of Sciences and their collaborators in the United States, Europe and Japan, among others.
The world’s largest fusion reactor, ITER, is currently being built in France. This is a critical advance for ITER and fusion, according to physicist Richard Pitts, who oversees plasma experiments and operations at ITER.
Pitts added that the EAST tests are critical because they revealed for the first time that tokamak plasmas could be maintained and tuned for very long pulses — more than 1,000 seconds, which is equivalent to the long pulses that ITER aims for in the future long.
Pitts noted numerous challenges with very long pulse operations, and it is quite reassuring for ITER to see that this has been achieved, even on a considerably smaller device.
According to Song Yuntao, co-author of the study, one of the key benefits of super-mode I was its ability to reduce energy losses near the edge of the plasma, where the superhot gas directly confronts the tokamak’s heat shield.
Song explained that if we equate nuclear fusion processes with lightning, the researchers aim to gather as many bolts as possible into a magnetic cage and transfer the energy stably and sustainably for human use.
Song said the new mode of operation discovered on EAST allows Chinese scientists to capture more lightning flashes while maintaining steady-state operation for a long time.
Why is the new Super I mode important?
Fusion is the process by which two hydrogen atoms fuse to produce a helium atom while emitting tremendous energy, which powers the sun and stars.
Scientists aim to recreate the power of the sun on Earth and want the fusion process to be well controlled. They expect society to be powered in a new, much more efficient and environmentally friendly way.
One of the most promising routes to managed nuclear fusion is through tokamaks such as EAST and ITER. The challenge is still producing high-performance plasma and confining it long enough for the hydrogens to combine to produce net power as the sun does.
Liu Zhihong of the Hefei Institute of Plasma Physics said fusion scientists use operating parameters or “modes” to control the state of the plasma. These factors include temperature and energy.
Most tokamaks today, including EAST, run in high-closure mode or H-mode. Large reactors like ITER were made possible by H-mode, which was first detected on a tokamak in Germany in 1982. H-mode a was at least 100 times more effective in plasma confinement than the previous low containment mode.
However, a significant disadvantage of H-mode operation is that it could cause a sudden release of energy at the edge of the plasma and damage nearby materials.
To avoid surface damage, scientists have recently explored mode I, also known as enhanced containment mode, where the fusion energy is released through a more continuous process.
But, the scientists were amazed to find that compared to the I-mode, the new mode greatly improved the energy confinement, earning it the nickname Super I-mode. Pitts pointed out that since the super-I mode has only been observed on EAST, it is unclear whether ITER could use it. He added that ITER plans to operate in “advanced scenarios” similar to the EAST experiments.
“These advanced scenarios allow you to run very long plasma durations – up to 3,000 seconds on ITER. In H mode, ITER can go up to a plasma duration of about 500 seconds,” Pitts said.
EAST is the first of its kind to run at 1,000 pulses or less. Since operating in 2006, the reactor has supported thousands of experiments conducted internally and with the global fusion community.