Active tungsten expulsion in ELM-absent H-mode plasmas via on-demand ELM triggering with lithium granule injection
Year: 2025
Type: article
Abstract: Lithium granules gravitationally injected into the upper X-point region demonstrated on-demand edge-localized modes (ELM) triggering in otherwise ELM-suppressed H-mode plasmas on the Experimental Advanced Superconducting Tokamak. Sub-mm lithium granules dropped into enhanced D-alpha H-mode plasmas achieved a high triggering efficiency, while enabling ELM frequencies from several to hundreds of hertz. Core radiation from heavy impurities, dominated by W, was reduced by up to 60%, and the normalized energy confinement increased by up to 30%. At low injection frequencies, ELMs of substantially reduced size compared to spontaneous type-I ELMs were observed. At high injection frequencies, a transition to a mixed ELM phase occurred, characterized by intermittent larger ELMs and suppression of the quasi-coherent mode, achieving the most significant W reduction and energy confinement improvement. These results highlight a promising pathway for active W control via controlled, small ELMs in long-pulse, high-performance scenarios.
Source: Nuclear Fusion
Authors: Z. Sun, R. Maingi, Y.X. Cheng, Y.Z. Qian, W. Xu, Z. Wang, L. Zhang, A. Bortolon, Y.M. Duan, M. Huang, Y.F. Wang, J. Huang, T. Zhang, L. Chen, W. Wang, J.H. Yang, Y.Y. Li, D.G. Wu, K. Jia, H.L. Zhao, Q. Zhang, K. Tritz, H.Q. Wang, R. Lunsford, A. Nagy, A. Diallo, G.Z. Zuo, X.Z. Gong, J.S. Hu, the EAST Team
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,595
Awards: G1715826441, G1890678732, G663282964
OpenAlex ID: W4413839549