The study revealed that inverting the form of plasma in thermonuclear synthesis reactors can enhance their performance. To ensure the commercial viability of thermonuclear energy plants, it is crucial to maintain the plasma conditions necessary for synthesis reactions. However, high temperatures and plasma densities often result in parameter gradients, leading to unstable localized regimes, such as edge localized modes (ELM).
ELMs are instabilities that occur on the plasma edge and can damage reactor walls. The shape of plasma in cross-section significantly influences ELM. Researchers have focused on “triangular plasma,” which describes the deviation of plasma form from oval. Traditionally, positive triangularity plasma has been studied, resembling the letter “D” shape with a vertical central Tokamak rack.
Recent studies have shifted to negative triangularity plasma, where the vertical part is positioned at the outer wall. Data from the DIII-D national thermonuclear fusion facility showed that this plasma shape is mostly stable. The findings were published in the journal Physical Review Letters.
Experiments with negative triangularity plasma on the DIII-D Tokamak demonstrated ELM restriction by preventing temperature and pressure gradient formation. Even with high heating power, plasma with strong negative triangularity remained stable and did not exhibit ELM.
This study, supported by extensive diagnostic data and enhanced modeling on the DIII-D Tokamak, confirmed improved plasma stability across various conditions. The internal stability achieved with negative triangularity surpasses ELM suppression through other methods, suggesting it as a promising approach for designing thermonuclear energy systems and emphasizing the need for further research in this area.