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Uncertainty quantification of EFIT reconstructions using the EFIT-AI database

POSTER

Abstract

The EFIT-AI database is a collection of tokamak discharges with multiple equilibrium reconstructions. This database is being developed for the EFIT-AI project because high quality data and open access to it are increasingly becoming a requirement for advancing tokamak science with Data Science methods. Currently, the database features the 2019 DIII-D campaign (approximately 2500 discharges) with 4 different EFIT reconstructions: 1. Magnetics-only EFIT, 2. Magnetics+MSE EFIT, 3. OMFIT-automated kinetic EFITs, and 4. CAKE-automated kinetic EFITs. Here we examine the sensitivity of the solution vector(s) from various EFIT reconstructions to the measurements, which enter EFIT as constraints. These constraints are used in the least-squares square minimization of EFIT to find the optimal fitting coefficients for the pressure and $F=RB_{\phi}$ profiles. We use correlation matrices and singular-value decomposition (SVD) to carry out the uncertainty quantification. Preliminary results show strong correlations between the magnetic measurements. SVD splits the time-dependent measurements into separate spatial and temporal parts, with the singular values indicating the significance of each eigenmode. SVD can be used to filter out the eigenmodes with low singular values.

Presenters

  • Cihan Akcay

    General Atomics

Authors

  • Cihan Akcay

    General Atomics

  • Joseph T Mcclenaghan

    General Atomics, General Atomics - San Diego, Oak Ridge National Laboratory

  • Torrin A Bechtel

    ORAU, GA, Orau, General Atomics / ORAU, University of Wisconsin - Madison

  • David Orozco

    General Atomics

  • Yueqiang Q Liu

    General Atomics - San Diego, General Atomics

  • Lang L Lao

    General Atomics - San Diego, General Atomics

  • Scott E Kruger

    Tech-X Corp, Tech-X

  • Eric C Howell

    Tech-X Corp

  • Jarrod Leddy

    Tech-X Corp, Tech-X

  • Sandeep Madireddy

    Argonne National Lab, Argonne National Laboratory, ANL

  • Jaehoon Koo

    Argonne National Laboratory, ANL

  • Samuel W Williams

    LBNL, Lawrence Berkeley National Laboratory

  • Alexei Pankin

    Princeton Plasma Physics Laboratory, PPPL