April 4-6

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Author: Alejandro Campos
Requested Type: Poster
Submitted: 2022-03-03 19:50:47

Co-authors: B. Zhu, I. Joseph, M. Holec, C. Vogl, A. Dimits, B. Southworth

Contact Info:
Lawrence Livermore National Laboratory
7000 East Ave.
Livermore, CA   94551

Abstract Text:
Finite-element schemes support arbitrarily high order approximations that are typically better suited to modern GPU architectures due to the larger arithmetic intensity (flop/byte ratio). Moreover, the finite-element exterior-calculus approach to spatial discretizations coupled with generally symplectic time integrators is able to conserve quadratic invariants of the underlying model [1]. We explore the application of these algorithms to simulations of drift-wave turbulence driven by background gradients and magnetic-field curvature, as dictated by the extended Hasegawa-Wakatani model. The high-order MFEM finite-element framework is used to solve the governing equations. Both continuous Galerkin (CG) and discontinuous Galerkin (DG) methods are explored, and particular emphasis is placed on quantifying the effect of DG upwinding—a feature generally required to suppress unphysical high-mode oscillations. The accuracy of the solutions is assessed through comparisons against results from finite-difference simulations previously published in the literature. Quantities such as energy spectra, the PDF of the turbulent flux, and the evolution of generalized energy and enstrophy are used for these comparisons. Results are also provided on stability requirements and limitations as the order of the finite-element polynomials is increased. [1] M. Holec et al. “Arbitrary Order Energy and Enstrophy Conserving Finite Element Methods for 2D Incompressible Fluid Dynamics and Drift-Reduced magnetohydrodynamics,” https://arxiv.org/abs/2202.13022/

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was supported by LLNL Laboratory Directed Research and Development project 20-ERD-038.

This abstract and poster falls under the category of "Computer Simulation of Plasmas".