Recent advancements in plasma physics could reshape the future of fusion energy, especially as researchers tackle one of the significant challenges facing tokamaks—error fields. A team led by Q.M. Hu from the Princeton Plasma Physics Laboratory has unveiled a method for non-disruptive error field measurement in low safety factor plasmas at the DIII-D National Fusion Facility. Their findings, recently published in ‘Nuclear Fusion’, could have profound implications for the ITER project, which aims to demonstrate the viability of fusion as a large-scale energy source.
In their study, Hu and his colleagues built upon previous work that introduced a technique to identify intrinsic error fields (EFs) with minimal disruption risk. This innovative approach allows for the healing of driven magnetic islands, a common issue in plasma confinement. By reducing the time between the occurrence of a locked mode and the control action to just 10 milliseconds and increasing plasma density by 50% to 100%, they achieved non-disruptive EF measurement at safety factors of q95 = 4.5 and 3.9. However, at q95 = 3.2, they found that a 50% correction of the intrinsic EF was necessary for effective island healing.
Hu emphasized the importance of these findings, stating, “The ability to control error fields non-disruptively opens new avenues for maintaining plasma stability, which is crucial for the success of future fusion reactors like ITER.” This research not only enhances our understanding of plasma behavior but also provides a pathway to mitigate disruptions that can halt operations and lead to costly downtime.
The implications for the energy sector are significant. As the world increasingly turns towards sustainable energy solutions, the success of fusion energy could provide a nearly limitless source of clean energy. The ability to manage error fields effectively means that ITER could operate more reliably, bringing us closer to commercial fusion power.
Moreover, the study’s numerical modeling using the TM1 code demonstrated that promptly turning off the 3D coil current can effectively reduce the size of magnetic islands, while increasing plasma viscosity through higher density aids in healing these islands. The simulations suggest that for ITER, taking control action between 100 to 500 milliseconds after a locked mode occurrence could lead to successful island healing, leveraging the longer resistive time of the ITER design.
As researchers continue to refine these techniques, the potential for fusion energy to become a viable player in the global energy market grows. This work not only provides essential insights for ITER but also sets the stage for future advancements in fusion technology. For more information on Q.M. Hu’s research, you can visit the Princeton Plasma Physics Laboratory at lead_author_affiliation.
