Numerical accuracy and convergence with EMC3-EIRENE

Kristel GHOOS; Heinke FRERICHS; Wouter DEKEYSER; Giovanni SAMAEY; Martine BAELMANS

doi:10.1088/2058-6272/ab5866

Plasma Science and Technology > 2020 > 22(5): 54001-054001. > DOI: 10.1088/2058-6272/ab5866

Kristel GHOOS, Heinke FRERICHS, Wouter DEKEYSER, Giovanni SAMAEY, Martine BAELMANS. Numerical accuracy and convergence with EMC3-EIRENE[J]. Plasma Science and Technology, 2020, 22(5): 54001-054001. DOI: 10.1088/2058-6272/ab5866

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Numerical accuracy and convergence with EMC3-EIRENE

¹KU Leuven, Department of Mechanical Engineering, B-3001, Leuven, Belgium
² University of Wisconsin Madison, Department of Engineering Physics, WI 53706, United States of America
³KU Leuven, Department of Computer Science, B-3001, Leuven, Belgium

Funds: The work of K Ghoos was sponsored by Flanders Innovation and Entrepreneurship (IWT.141064) and a travel grant (V4.128.18N) from Research Foundation—Flanders (FWO). Parts of the work are supported by the Research Foundation Flanders (FWO) under project grant G078316N. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation—Flanders (FWO) and the Flemish Government—department EWI.

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Received Date: July 21, 2019
Revised Date: November 13, 2019
Accepted Date: November 17, 2019

Graphical Abstract

Abstract

Abstract

The iterative Monte Carlo (MC) code EMC3-EIRENE is frequently used for plasma edge simulations in 3D applications. So far, a quantitative evaluation of the numerical quality of the code results remains an open issue. In this paper, we demonstrate a framework for the practical assessment of accuracy and convergence with EMC3-EIRENE. Moreover, we provide a first accuracy analysis with EMC3-EIRENE for a DIII-D divertor edge plasma case. First, we introduce post-processing averaging to efficiently reduce the variance of the statistical error. Then, we estimate the deterministic error contributions based on their theoretical reduction rates by comparing solutions with a different grid resolution, time step, or number of MC particles per iteration. Finally, using parameterized expressions for the error and the computational time, suitable numerical parameters are determined to achieve faster and/or more accurate results. We found that simulations can be more than twice as fast without losing accuracy by making use of post-processing averaging and choosing optimal parameters. In addition, we conclude that the discretization error is the dominant error contribution for the case selected in this paper, which demonstrates the importance of constructing an adequate mesh.
- convergence,
- Monte Carlo,
- numerics,
- plasma edge,
- EMC3-EIRENE

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References (19)

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