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Scientists have figured out how to tame turbulence in a nuclear fusion reactor
September 2, 10:02
Researchers working on the DIII-D tokamak in San Diego, California, have demonstrated for the first time that Alfven eigenmodes can not only hinder nuclear fusion but can actually improve it. This discovery could significantly enhance heat retention in plasma, which is critical for achieving the high temperatures necessary for efficient controlled nuclear fusion.
DIII-D and Alfven Modes
DIII-D is the largest tokamak in North America, where magnetic fields heat plasma to 150 million degrees Celsius, which is about ten times the temperature at the core of the Sun. Under such extreme conditions, heavy isotopes of hydrogen fuse, releasing a significant amount of energy.
It was previously believed that Alfven eigenmodes only interfered with this process, however, new results indicate that these plasma waves can generate plasma flows and electromagnetic currents that, in turn, create a drift flow. This drift flow helps to tame turbulence in the tokamak, leading to increased temperatures of ions and electrons, as well as reduced heat losses, allowing heat to be retained in the core of the plasma.
To conduct the measurements, scientists used a diagnostic tool based on the Motional Stark Effect (MSE). This method involves shooting a beam of neutral deuterium atoms into the plasma, after which the impact of the magnetic field is measured by observing changes in the polarization of light. As a result of the research, a 5 percent change in the safety coefficient was recorded over 20 milliseconds. The safety coefficient describes how magnetic field lines follow the long and short dimensions of the chamber, and their structure is compared to spiral potato fries on a stick.
These new results represent an important step in the development of nuclear fusion technologies, which could provide a stable and practically waste-free source of energy for future generations. As the world seeks alternatives to traditional energy sources, such research could significantly impact the energy landscape, promoting the transition to cleaner and more renewable energy sources.
The importance of these discoveries underscores the growing role of nuclear fusion in the global context of energy security and the fight against climate change.
Interestingly, new research in plasma physics is opening new horizons for technologies related to controlled nuclear fusion. For example, scientists recently found that stretching manganese telluride can change the Hall effect without heating, which could also significantly impact the energy technologies of the future.