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Title: Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling

Abstract

An integrated-modeling workflow has been developed in this paper for the purpose of performing predict-first analysis of transient-stability experiments. Starting from an existing equilibrium reconstruction from a past experiment, the workflow couples together the EFIT Grad-Shafranov solver [L. Lao et al., Fusion Sci. Technol. 48, 968 (2005)], the EPED model for the pedestal structure [P. B. Snyder et al., Phys. Plasmas 16, 056118 (2009)], and the NEO drift-kinetic-equation solver [E. A. Belli and J. Candy, Plasma Phys. Controlled Fusion 54, 015015 (2012)] (for bootstrap current calculations) in order to generate equilibria with self-consistent pedestal structures as the plasma shape and various scalar parameters (e.g., normalized β, pedestal density, and edge safety factor [q95]) are changed. These equilibria are then analyzed using automated M3D-C1 extended-magnetohydrodynamic modeling [S. C. Jardin et al., Comput. Sci. Discovery 5, 014002 (2012)] to compute the plasma response to three-dimensional magnetic perturbations. This workflow was created in conjunction with a DIII-D experiment examining the effect of triangularity on the 3D plasma response. Several versions of the workflow were developed, and the initial ones were used to help guide experimental planning (e.g., determining the plasma current necessary to maintain the constant edge safety factor in various shapes). Subsequentmore » validation with the experimental results was then used to revise the workflow, ultimately resulting in the complete model presented here. We show that quantitative agreement was achieved between the M3D-C1 plasma response calculated for equilibria generated by the final workflow and equilibria reconstructed from experimental data. A comparison of results from earlier workflows is used to show the importance of properly matching certain experimental parameters in the generated equilibria, including the normalized β, pedestal density, and q95. On the other hand, the details of the pedestal current did not significantly impact the plasma response in these equilibria. A comparison to the experimentally measured plasma response shows mixed agreement, indicating that while the equilibria are predicted well, additional analysis tools may be needed. In conclusion, we note the implications that these results have for the success of future predict-first studies, particularly the need for scans of uncertain parameters and for close collaboration between experimentalists and theorists.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2];  [1]
  1. General Atomics, San Diego, CA (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1436754
Alternate Identifier(s):
OSTI ID: 1436208
Grant/Contract Number:  
FG02-95ER54309; FC02-06ER54873; FC02-04ER54698; SC0015499
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 25; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma confinement; numerical modeling; tokamaks; magnetohydrodynamics; plasma instabilities

Citation Formats

Lyons, B. C., Paz-Soldan, C., Meneghini, O., Lao, L. L., Weisberg, D. B., Belli, E. A., Evans, T. E., Ferraro, N. M., and Snyder, P. B. Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling. United States: N. p., 2018. Web. doi:10.1063/1.5025838.
Lyons, B. C., Paz-Soldan, C., Meneghini, O., Lao, L. L., Weisberg, D. B., Belli, E. A., Evans, T. E., Ferraro, N. M., & Snyder, P. B. Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling. United States. https://doi.org/10.1063/1.5025838
Lyons, B. C., Paz-Soldan, C., Meneghini, O., Lao, L. L., Weisberg, D. B., Belli, E. A., Evans, T. E., Ferraro, N. M., and Snyder, P. B. Mon . "Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling". United States. https://doi.org/10.1063/1.5025838. https://www.osti.gov/servlets/purl/1436754.
@article{osti_1436754,
title = {Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling},
author = {Lyons, B. C. and Paz-Soldan, C. and Meneghini, O. and Lao, L. L. and Weisberg, D. B. and Belli, E. A. and Evans, T. E. and Ferraro, N. M. and Snyder, P. B.},
abstractNote = {An integrated-modeling workflow has been developed in this paper for the purpose of performing predict-first analysis of transient-stability experiments. Starting from an existing equilibrium reconstruction from a past experiment, the workflow couples together the EFIT Grad-Shafranov solver [L. Lao et al., Fusion Sci. Technol. 48, 968 (2005)], the EPED model for the pedestal structure [P. B. Snyder et al., Phys. Plasmas 16, 056118 (2009)], and the NEO drift-kinetic-equation solver [E. A. Belli and J. Candy, Plasma Phys. Controlled Fusion 54, 015015 (2012)] (for bootstrap current calculations) in order to generate equilibria with self-consistent pedestal structures as the plasma shape and various scalar parameters (e.g., normalized β, pedestal density, and edge safety factor [q95]) are changed. These equilibria are then analyzed using automated M3D-C1 extended-magnetohydrodynamic modeling [S. C. Jardin et al., Comput. Sci. Discovery 5, 014002 (2012)] to compute the plasma response to three-dimensional magnetic perturbations. This workflow was created in conjunction with a DIII-D experiment examining the effect of triangularity on the 3D plasma response. Several versions of the workflow were developed, and the initial ones were used to help guide experimental planning (e.g., determining the plasma current necessary to maintain the constant edge safety factor in various shapes). Subsequent validation with the experimental results was then used to revise the workflow, ultimately resulting in the complete model presented here. We show that quantitative agreement was achieved between the M3D-C1 plasma response calculated for equilibria generated by the final workflow and equilibria reconstructed from experimental data. A comparison of results from earlier workflows is used to show the importance of properly matching certain experimental parameters in the generated equilibria, including the normalized β, pedestal density, and q95. On the other hand, the details of the pedestal current did not significantly impact the plasma response in these equilibria. A comparison to the experimentally measured plasma response shows mixed agreement, indicating that while the equilibria are predicted well, additional analysis tools may be needed. In conclusion, we note the implications that these results have for the success of future predict-first studies, particularly the need for scans of uncertain parameters and for close collaboration between experimentalists and theorists.},
doi = {10.1063/1.5025838},
journal = {Physics of Plasmas},
number = 5,
volume = 25,
place = {United States},
year = {Mon May 07 00:00:00 EDT 2018},
month = {Mon May 07 00:00:00 EDT 2018}
}

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Works referencing / citing this record:

The effect of plasma shape and neutral beam mix on the rotation threshold for RMP-ELM suppression
journal, March 2019