Combination of micro-macro and spatially hybrid fluid-kinetic approach for hydrogenic plasma edge neutrals

Niels Horsten, Mathias Groth*, Wouter Dekeyser, Wim Van Uytven, Stefano Carli, JET Contributors

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)
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A new hybrid fluid-kinetic approach for the hydrogenic neutrals (atoms and molecules) in the plasma edge is presented. The hybrid approach combines a fully kinetic model for the atoms in the low-collisional regions near the vessel wall, and for the molecules in the whole plasma edge domain, with a micro-macro approach for atoms originating from recycling at the divertor targets, volumetric recombination, and dissociation of molecules. With the micro-macro approach, the originally scattering-dominated collision term due to charge-exchange collisions in the kinetic equation is transformed to an absorption-dominated term, while a large part of the neutral population is treated through a fluid approach. For JET L-mode plasmas, the premature termination of Monte Carlo particle trajectories in the hybrid approach leads to a reduction of the CPU time by approximately a factor 3 for a high-recycling case and by approximately a factor 11 for a partially detached case compared with a simulation with fully kinetic neutrals and the same amount of particles. For coupled fluid plasma - hybrid neutral simulations - the hybrid approach predicts the plasma divertor target profiles with a maximum hybrid-kinetic discrepancy of approximately 30%.

Original languageEnglish
Article number202100188
Number of pages13
JournalContributions to Plasma Physics
Issue number5-6
Early online date27 Mar 2022
Publication statusPublished - Jun 2022
MoE publication typeA1 Journal article-refereed


  • fluid approximation
  • kinetic model
  • neutrals
  • plasma edge modelling


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