Impact of model uncertainty on SPARC operating scenario predictions with empirical modeling

Fuente: arXiv
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Main Authors: Saltzman, A., Rodriguez-Fernandez, P., Body, T., Ho, A., Howard, N. T.
Format: Preprint
Published: 2025
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author Saltzman, A.
Rodriguez-Fernandez, P.
Body, T.
Ho, A.
Howard, N. T.
author_facet Saltzman, A.
Rodriguez-Fernandez, P.
Body, T.
Ho, A.
Howard, N. T.
contents Understanding and accounting for uncertainty helps to ensure next-step tokamaks such as SPARC will robustly achieve their goals. While traditional Plasma OPerating CONtour (POPCON) analyses guide design, they often overlook the significant impact of uncertainties in scaling laws, plasma profiles, and impurity concentrations on performance predictions. This work confronts these challenges by introducing statistical POPCONs, which leverage Monte Carlo analysis to quantify the sensitivity of SPARC's operating points [1] to these crucial variables. For profiles, a physically motivated gradient-based functional form is introduced. We further develop a multi-fidelity Bayesian optimization workflow that effectively identifies operating points maximizing the probability of meeting performance goals, which gives a significant speed-up over brute force methods. Our findings reveal that accounting for these uncertainties leads to an optimal operating point different from deterministic predictions, which balances H-mode access, confinement, impurity dilution, and auxiliary power.
format Preprint
id arxiv_https___arxiv_org_abs_2506_09879
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Impact of model uncertainty on SPARC operating scenario predictions with empirical modeling
Saltzman, A.
Rodriguez-Fernandez, P.
Body, T.
Ho, A.
Howard, N. T.
Plasma Physics
Understanding and accounting for uncertainty helps to ensure next-step tokamaks such as SPARC will robustly achieve their goals. While traditional Plasma OPerating CONtour (POPCON) analyses guide design, they often overlook the significant impact of uncertainties in scaling laws, plasma profiles, and impurity concentrations on performance predictions. This work confronts these challenges by introducing statistical POPCONs, which leverage Monte Carlo analysis to quantify the sensitivity of SPARC's operating points [1] to these crucial variables. For profiles, a physically motivated gradient-based functional form is introduced. We further develop a multi-fidelity Bayesian optimization workflow that effectively identifies operating points maximizing the probability of meeting performance goals, which gives a significant speed-up over brute force methods. Our findings reveal that accounting for these uncertainties leads to an optimal operating point different from deterministic predictions, which balances H-mode access, confinement, impurity dilution, and auxiliary power.
title Impact of model uncertainty on SPARC operating scenario predictions with empirical modeling
topic Plasma Physics
url https://arxiv.org/abs/2506.09879