Nuclear Fushion | |
Estimating cross-field particle transport at the outer midplane of TCV by tracking filaments with machine learning | |
article | |
W. Han1  N. Offeddu2  T. Golfinopoulos1  C. Theiler2  J.L. Terry1  C. Wüthrich2  D. Galassi2  C. Colandrea2  E.S. Marmar1  the TCV Team2  | |
[1] MIT Plasma Science and Fusion Center;École Polytechnique Fédérale de Lausanne ,(EPFL), Swiss Plasma Center | |
关键词: negative triangularity; edge/SOL turbulence; machine learning; gas puff imaging; particle transport; tokamak; | |
DOI : 10.1088/1741-4326/acdae5 | |
来源: Institute of Physics Publishing Ltd. | |
【 摘 要 】
Cross-field transport of particles in the boundary region of magnetically confined fusion plasmas is dominated by turbulence. Blobs, intermittent turbulent structures with large amplitude and a filamentary shape appearing in the scrape-off layer (SOL), are known from theoretical and experimental studies to be the main contributor to the cross-field particle transport. The dynamics of blobs differs depending on various plasma conditions, including triangularity ( δ ). In this work, we analyze triangularity dependence of the cross-field particle transport at the outer midplane of plasmas with delta = +0.38 , +0.15, −0.14, and −0.26 on the Tokamak à Configuration Variable, using our novel machine learning (ML) blob-tracking approach applied to gas puff imaging data. The cross-field particle flux determined in this way is of the same order as the overall transport inferred from KN1D, GBS, and SOLPS-ITER simulations, suggesting that the blobs identified by the ML blob-tracking account for most of the cross-field particle transport in the SOL. Also, the ML blob-tracking and KN1D show a decrease in the cross-field particle transport asδbecomes more negative. The blob-by-blob analysis of the result from the tracking reveals that the decrease of cross-field particle transport with decreasingδis accompanied by a decrease in the number of blobs in a fixed time, which tend to have larger area and lower radial speed. Also, the blobs in these plasmas are in the connected sheath regime, and show a velocity scaling consistent with the two-region model.
【 授权许可】
Unknown
【 预 览 】
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RO202307170000723ZK.pdf | 4145KB | download |