Particle conservation in numerical models of the tokamak plasma edge

Kotov, Vladislav

doi:10.1063/1.4980858

Journal Article

FZJ-2017-03115

Particle conservation in numerical models of the tokamak plasma edge

Kotov, V. (Corresponding author)FZJ*

2017
American Institute of Physics [S.l.]

Physics of plasmas 24(4), 042511 - (2017) [10.1063/1.4980858]

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Please use a persistent id in citations: http://hdl.handle.net/2128/18131 doi:10.1063/1.4980858

Abstract: The test particle Monte-Carlo models for neutral particles are often used in the tokamak edge modelling codes. The drawback of these models is that the self-consistent solution suffers from random error introduced by the statistical method. A particular case where the onset of nonphysical solutions can be clearly identified is the violation of the global particle balance due to non-converged residuals. There are techniques that can reduce the residuals—such as internal iterations in the code B2-EIRENE—but they may pose severe restrictions on the time-step and slow down the computations. Numerical diagnostics described in this paper can be used to unambiguously identify when the too large error in the global particle balance is due to finite-volume residuals, and their reduction is absolutely necessary. Algorithms that reduce the error while allowing large time-step are also discussed.

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