In a groundbreaking achievement, researchers at the CEA, IRFM in Saint-Paul-lez-Durance, France, have pushed the boundaries of nuclear fusion technology. Led by Dr. T. Fonghetti, the team set a new record on the WEST Tokamak, operating long-duration plasmas in a tungsten environment with unprecedented stability and control. This milestone, published in the journal Nuclear Fusion, translates to ‘Nuclear Fusion’ in English, could revolutionize the energy sector by bringing us closer to sustainable, clean fusion power.
The WEST Tokamak, designed to mimic the conditions of a future fusion power plant, achieved an injected energy of 1.15 GJ and sustained a plasma duration of 364 seconds. This is a significant leap forward in long-pulse operation, a critical factor for commercial fusion reactors. “Achieving such long pulses is a major step towards demonstrating the viability of fusion power,” Dr. Fonghetti explained. “It shows that we can maintain stable plasma conditions over extended periods, which is essential for generating continuous power.”
The success of this experiment was underpinned by advanced integrated modeling using the High Fidelity Plasma Simulator (HFPS). This European IMAS-coupled version of JETTO/JINTRAC integrates various physics-driven modules into a unified framework, allowing for precise predictions and control of plasma behavior. The team utilized a reduced model for Lower-Hybrid heating and Current-Drive (LHCD) and the quasi-linear turbulent transport model TGLF to predict long pulses up to the Last Closed Flux Surface (LCFS). This predictive capability is crucial for optimizing plasma performance and avoiding machine limitations.
One of the key findings was the importance of varying non-inductive current-drive actuators, such as plasma current, electron density, and LHCD power. By carefully adjusting these parameters, the researchers were able to ease access to fully non-inductive discharges, a crucial step towards sustainable fusion power. “Decreasing the plasma current, for instance, can significantly improve the operational domain,” Dr. Fonghetti noted. “But it requires a delicate balance of other factors to avoid pushing the machine beyond its limits.”
The experiments also validated the predictive models, showing quantitative agreement with the actual outcomes. This alignment between prediction and reality is a testament to the robustness of the modeling tools used. Moreover, the team explored the use of Electron Cyclotron Current Drive (ECCD) for maintaining MHD stability, opening up new avenues for future research.
The implications of this research are far-reaching for the energy sector. Long-pulse operation is a cornerstone of commercial fusion reactors, and the ability to predict and control plasma behavior over extended periods is a significant step towards making fusion power a reality. As Dr. Fonghetti puts it, “This work brings us closer to a future where fusion power can provide a sustainable, clean energy source. The insights gained from these experiments will be invaluable as we continue to develop and refine fusion technologies.”
The publication of these findings in Nuclear Fusion marks a significant milestone in the journey towards commercial fusion power. As the energy sector grapples with the challenges of climate change and the need for sustainable energy sources, advancements like these offer a beacon of hope. The work done by Dr. Fonghetti and his team at CEA, IRFM is not just a scientific achievement but a step towards a cleaner, more sustainable future. The energy sector is watching closely, and the potential commercial impacts are immense. The future of energy could very well be shaped by the plasma pulses sustained in the WEST Tokamak.
