First access to ELM-free negative triangularity at low aspect ratio
Year: 2024
Type: article
Abstract: A plasma scenario with negative triangularity (NT) shaping is achieved on MAST-U for the first time. While edge localized modes (ELMs) are eventually suppressed as the triangularity is decreased below δ ≲ − 0.06 , an extended period of H-mode operation with Type-III ELMs is sustained at less negative δ even through access to the second stability region for ideal ballooning modes is closed. This documents a qualitative difference from the ELM-free access conditions documented in NT scenarios on conventional aspect ratio machines. The electron temperature at the pedestal top drops across the transition to ELM-free operation, but a steady rise in core temperature as δ is decreased allows for similar normalized β in the ELM-free NT and H-mode positive triangularity shapes.
Source: Nuclear Fusion
Authors: A.O. Nelson, C. Vincent, H. Anand, J. Lovell, J.F. Parisi, H.S. Wilson, K. Imada, W.P. Wehner, M. Kochan, S. Blackmore, G. McArdle, S. Guizzo, L. Rondini, S. Freiberger, C. Paz-Soldan, the MAST-U Team
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,470
Awards: G121915436, G1645119126, G203625172, G2988778103, G333530719, G403017339, THE DIII-D NATIONAL FUSION PROGRAM AND ADVANCED FUSION TECHNOLOGY RESEARCH AND DEVELOPMENT, DIVERTOR PHYSICS AND CONTROL ON THE MAST-U TOKAMAK, RESISTIVE STABILITY AND SHAPE OPTIMIZATION RESEARCH IN NSTX-U, UKAEA / EPSRC Fusion Grant 2022/27, RESISTIVE STABILITY AND SHAPE OPTIMIZATION RESEARCH IN NSTX-U, THE DIII-D NATIONAL FUSION PROGRAM AND ADVANCED FUSION TECHNOLOGY RESEARCH AND DEVELOPMENT, G8269158468, THE DIII-D FUSION RESEARCH PROGRAM AND ADVANCED FUSION TECHNOLOGY RESEARCH AND DEVELOPMENT, G8906985441
OpenAlex ID: W4403628664