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On the accuracy of the binary-collision algorithm in particle-in-cell simulations of magnetically confined fusion plasmas

Published online by Cambridge University Press:  19 April 2021

Timo P. Kiviniemi*
Affiliation:
Department of Applied Physics, Aalto University, P.O. Box 11100, 00076Aalto, Finland
Eero Hirvijoki
Affiliation:
Department of Applied Physics, Aalto University, P.O. Box 11100, 00076Aalto, Finland
Antti J. Virtanen
Affiliation:
Department of Applied Physics, Aalto University, P.O. Box 11100, 00076Aalto, Finland
*
Email address for correspondence: timo.kiviniemi@aalto.fi

Abstract

Ideally, binary-collision algorithms conserve kinetic momentum and energy. In practice, the finite size of collision cells and the finite difference in the particle locations affect the conservation properties. In the present work, we investigate numerically how the accuracy of these algorithms is affected when the size of collision cells is large compared with gradient scale length of the background plasma, a parameter essential in full-$f$ fusion plasma simulations. Additionally, we discuss implications for the conserved quantities in drift-kinetic formulations when fluctuating magnetic and electric fields are present: we suggest how the accuracy of the algorithms could potentially be improved with minor modifications.

Type
Research Article
Copyright
Copyright © The Author(s), 2021. Published by Cambridge University Press

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References

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