HIPED: Machine Learning Framework for Spherical Tokamak Pedestal Prediction and Optimization

Fuente: arXiv
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Main Authors: Parisi, J. F., Clark, J. G., Berkery, J. W., Bowman, C., Fitzpatrick, C. J., Kaye, S. M., Lampert, M.
Format: Preprint
Published: 2025
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author Parisi, J. F.
Clark, J. G.
Berkery, J. W.
Bowman, C.
Fitzpatrick, C. J.
Kaye, S. M.
Lampert, M.
author_facet Parisi, J. F.
Clark, J. G.
Berkery, J. W.
Bowman, C.
Fitzpatrick, C. J.
Kaye, S. M.
Lampert, M.
contents We introduce a Machine Learning framework, HIPED (HeIght and width Predictor for Edge Dynamics), for predicting and optimizing pedestal and core performance in spherical tokamak plasmas. Trained on pedestal and core datasets from the third MAST-U campaign, HIPED provides accurate estimates of pedestal height and width. The results reveal notable differences compared with conventional aspect-ratio studies; for instance, a simple power-law relation between pedestal width and height has very low accuracy. Instead, additional parameters such as normalized plasma pressure, elongation, and Greenwald fraction significantly improve accuracy. HIPED can also be trained only on `control room parameters' to inform experimentalists of which controllable parameters to adjust for improving core-integrated performance. The framework further includes a multi-objective optimization scheme that helps guide experimental planning and optimization. We find Pareto-optimal discharges with respect to various features, including distance from edge-localized modes and normalized plasma pressure, track their parameter trajectories over time, and identify the control room parameters required for these Pareto-optimal discharges. This provides a framework for systematically optimizing core and edge performance according to different experimental priorities.
format Preprint
id arxiv_https___arxiv_org_abs_2504_19861
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle HIPED: Machine Learning Framework for Spherical Tokamak Pedestal Prediction and Optimization
Parisi, J. F.
Clark, J. G.
Berkery, J. W.
Bowman, C.
Fitzpatrick, C. J.
Kaye, S. M.
Lampert, M.
Plasma Physics
We introduce a Machine Learning framework, HIPED (HeIght and width Predictor for Edge Dynamics), for predicting and optimizing pedestal and core performance in spherical tokamak plasmas. Trained on pedestal and core datasets from the third MAST-U campaign, HIPED provides accurate estimates of pedestal height and width. The results reveal notable differences compared with conventional aspect-ratio studies; for instance, a simple power-law relation between pedestal width and height has very low accuracy. Instead, additional parameters such as normalized plasma pressure, elongation, and Greenwald fraction significantly improve accuracy. HIPED can also be trained only on `control room parameters' to inform experimentalists of which controllable parameters to adjust for improving core-integrated performance. The framework further includes a multi-objective optimization scheme that helps guide experimental planning and optimization. We find Pareto-optimal discharges with respect to various features, including distance from edge-localized modes and normalized plasma pressure, track their parameter trajectories over time, and identify the control room parameters required for these Pareto-optimal discharges. This provides a framework for systematically optimizing core and edge performance according to different experimental priorities.
title HIPED: Machine Learning Framework for Spherical Tokamak Pedestal Prediction and Optimization
topic Plasma Physics
url https://arxiv.org/abs/2504.19861