Abstract
Fusion whole device modeling simulations require comprehensive models that are simultaneously physically accurate, fast, robust, and predictive. In this paper we describe the development of two neural-network (NN) based models as a means to perform a snon-linear multivariate regression of theory-based models for the core turbulent transport fluxes, and the pedestal structure. Specifically, we find that a NN-based approach can be used to consistently reproduce the results of the TGLF and EPED1 theory-based models over a broad range of plasma regimes, and with a computational speedup of several orders of magnitudes. These models are then integrated into a predictive workflow that allows prediction with self-consistent core-pedestal coupling of the kinetic profiles within the last closed flux surface of the plasma. The NN paradigm is capable of breaking the speed-accuracy trade-off that is expected of traditional numerical physics models, and can provide the missing link towards self-consistent coupled core-pedestal whole device modeling simulations that are physically accurate and yet take only seconds to run.
Original language | English |
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Article number | 086034 |
Journal | Nuclear Fusion |
Volume | 57 |
Issue number | 8 |
DOIs | |
State | Published - Jul 12 2017 |
Funding
Work supported by the Office of Science of the US Department of Energy under Contract No. DE-SC0012656 (GA AToM SciDAC), DE-AC05-00OR22725 (ORNL AToM SciDAC), DE-FG02-95ER54309 (GA theory), DE-FC02-06ER54873 (ESL), DE-FC02-04ER54698 (DIII-D). This research used resources of the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231.
Keywords
- neural networks
- pedestal
- tokamak
- transport