Application of spatially hybrid fluid–kinetic neutral model on JET L-mode plasmas

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openAccess

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2021-06

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Mcode

Degree programme

Language

en

Pages

7

Series

Nuclear Materials and Energy, Volume 27

Abstract

We present a spatially hybrid fluid–kinetic neutral model that consists of a fluid model for the hydrogen atoms in the plasma grid region coupled to a kinetic model for atoms sampled at the plasma–void interfaces and a fully kinetic model for the hydrogen molecules. The atoms resulting from molecular dissociation are either treated kinetically (approach 1) or are incorporated in the fluid model (approach 2). For a low-density JET L-mode case, the hybrid method reduces the maximum fluid–kinetic discrepancies for the divertor strike-point electron densities and electron temperatures from approximately 150% to approximately 20% for approach 1 and to approximately 40% for approach 2. Although the simulations with purely fluid neutral model become more accurate for increasing upstream plasma density, we still observe a significant improvement by using the hybrid approach. When consuming the same CPU time in averaging the electron strike-point densities and temperatures over multiple iterations as for the simulations with fully kinetic neutrals, hybrid approach 1 reduces the statistical error with on average a factor 2.5. Hybrid approach 2 further increases this factor to approximately 3.3, at the expense of accuracy.

Description

| openaire: EC/H2020/633053/EU//EUROfusion

Keywords

Fluid approximation, Kinetic model, Neutrals, Plasma edge modeling

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Citation

Horsten, N, Groth, M, Blommaert, M, Dekeyser, W, Pérez, I P, Wiesen, S & JET Contributors 2021, ' Application of spatially hybrid fluid–kinetic neutral model on JET L-mode plasmas ', Nuclear Materials and Energy, vol. 27, 100969 . https://doi.org/10.1016/j.nme.2021.100969