In the quest to harness fusion energy, one of the persistent challenges has been managing edge localized modes (ELMs) in tokamaks. These periodic expulsions of heat and particles can significantly damage plasma-facing components, posing a substantial hurdle to the safe and efficient operation of fusion reactors. A recent study published in the journal “Nuclear Fusion” (formerly known as “Fusion Energy”) sheds new light on this issue, offering insights that could shape future ELM control strategies.
Led by Dr. E. Tomasina from the Università degli Studi di Padova and Consorzio RFX in Italy, the research team employed a combination of linear and quasi-linear modeling workflows to investigate the behavior of resonant magnetic perturbations (RMPs) as a tool for ELM control in the Mega Amp Spherical Tokamak Upgrade (MAST-U). The study utilized the MARS-F (single-fluid resistive MHD) and KilCA/QL-Balance (two-fluid kinetic) codes to analyze plasma responses to RMPs under realistic operational conditions.
One of the key findings of the study was the significant impact of intrinsic error fields (EFs) on ELM control strategies. The team developed a detailed model for the n = 2 intrinsic EF generated by the Poloidal Field coil system and computed the plasma response to this EF. The results revealed that the n = 2 EF is at least of the same order of magnitude as the perturbations introduced by the external RMP coils.
“This was a surprising finding,” noted Dr. Tomasina. “The intrinsic error field was found to significantly shift the optimal points of the analyzed metrics, affecting the effectiveness of ELM mitigation strategies. When the EF is unfavorably aligned with the external RMPs, it can be detrimental to core confinement and potentially explain the observation of locked-modes.”
The implications of this research are significant for the energy sector. Effective ELM control is crucial for the development of commercial fusion power plants. By understanding and addressing the impact of intrinsic error fields, researchers can design more robust ELM control strategies, enhancing the safety and performance of future fusion reactors.
Dr. Tomasina emphasized the importance of these findings for future developments: “Our results underscore the critical need for addressing intrinsic EF correction when designing ELM control strategies. This could pave the way for more efficient and reliable fusion energy systems, bringing us one step closer to a sustainable energy future.”
As the world continues to seek clean and sustainable energy sources, the insights from this study could play a pivotal role in advancing fusion energy technology. By tackling the challenges posed by ELMs and intrinsic error fields, researchers are making significant strides towards achieving practical and commercially viable fusion power.