In the quest for cleaner, more efficient nuclear fusion energy, researchers have long grappled with the challenge of managing impurities within the plasma, particularly tungsten (W). A recent breakthrough by Zhen Zhou, a scientist from the University of Science and Technology of China and Hefei Institutes of Physical Science, Chinese Academy of Sciences, sheds new light on how to mitigate tungsten accumulation in high-performance tokamak discharges. This discovery, published in the journal Nuclear Fusion, could have significant implications for the future of fusion energy and the commercial energy sector.
The study, conducted on the Experimental Advanced Superconducting Tokamak (EAST), revealed a novel method to reduce tungsten content using Ion Cyclotron Resonance Heating (ICRH). Previous methods, such as electron cyclotron resonance heating, have shown some success in controlling tungsten, but the new findings offer a more efficient approach. “Unlike previous methods, our approach with ICRH shows a slight change in plasma temperature but a significant reduction in toroidal rotational velocity,” Zhou explains. This reduction in rotational velocity, around 10 km/s, leads to a marked decrease in tungsten density and its spectral emissions in the Extreme Ultraviolet region.
The implications of this research are profound. Tungsten, a heavy metal used in tokamak walls, can accumulate in the plasma core, leading to cooling and reduced fusion performance. By reducing tungsten content, the efficiency and stability of fusion reactions can be significantly improved. This breakthrough could pave the way for more sustainable and commercially viable fusion power plants. “The reduction in toroidal rotation leads to less tungsten poloidal asymmetry and neoclassical pinch, which is more efficient in alleviating core tungsten accumulation,” Zhou elaborates. This finding could lead to more efficient and stable fusion reactions, bringing us closer to practical, commercial fusion energy.
The study also compared the effects of isotropic and anisotropic hydrogen (H) minority from ICRH on tungsten transport, providing deeper insights into the mechanisms at play. This detailed understanding could inform future designs and operational strategies for tokamaks, enhancing their performance and reliability. As fusion energy continues to gain traction as a potential solution to global energy challenges, research like this is crucial. It not only advances our scientific understanding but also brings us one step closer to harnessing the power of the stars for sustainable, clean energy on Earth. The research is published in the journal Nuclear Fusion, formerly known as Plasma Physics and Controlled Fusion.
