Abstract Details
Abstracts
Author: Omar Lopez
Requested Type: Poster
Submitted: 2026-03-20 11:54:14
Co-authors: P. Laiu, C. D. Hauck, M. T. Beidler
Contact Info:
Oak Ridge National Laboratory
ORNL PO Box 2008
Oak Ridge, TN 37831
USA
Abstract Text:
Toward a self-consistent coupling of the Kinetic Orbit Runaway electrons Code (KORC) with the NIMROD extended-MHD code, we replace NIMROD's internal solver for the projection of runaway electron moments onto finite element space with PETSc (the Portable, Extensible Toolkit for Scientific Computation). A central component is the Magnetic Axis Basis (MAB), which collapses the degenerate finite element nodes at the magnetic axis into a single degree of freedom and enforces poloidal periodicity, yielding a well-posed reduced system. Verification is performed against DepoPy, an independent Python finite element reference implementation; agreement at machine precision is obtained for bilinear and biquadratic discretizations in both codes, and extension to arbitrary higher-order elements is underway. Statistical noise in the projected current, which becomes significant when runaway electrons are sparsely distributed, is addressed through Tikhonov regularization by penalizing large spatial gradients in the solution. This work establishes the solver infrastructure for scalable, high-fidelity runaway electron current deposition in self-consistent KORC-NIMROD simulations.
*This work is supported by the US DOE under contract DE-AC05-00OR22725
Characterization: 4.0
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