Journal Article

FZJ-2021-01549

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Three-dimensional first principles simulation of a hydrogen discharge

Chew, J. (Corresponding author)FZJ* ; Gibbon, P.FZJ* ; Brömmel, D.FZJ* ; Wauters, T.FZJ* ; Gribov, Y. ; de Vries, P.

2021
IOP Publ. Bristol

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Please use a persistent id in citations: http://hdl.handle.net/2128/27569  doi:10.1088/1361-6587/abdd75

Abstract: Townsend discharge theory is commonly used to describe and approximate the ionisation fraction growth rate in the very early phase of plasma initiation in tokamak devices via ohmic breakdown. The prediction of the ionisation fraction growth rate is done most commonly with continuum or kinetic models, which in turn boil down to the relation between the first Townsend's coefficient α, pressure p and electric field strength E (namely, α/p and E/p). To date there are few computational models that attempt to simulate the ionisation fraction growth rate via explicit modelling of each ionisation event through electron-neutral collisions. This is largely due to the challenge of addressing the exponential growth of charged particles from ionisation processes, combined with the high computational cost of N-body simulation. In this work, a new fully three-dimensional, first-principles model of a Townsend hydrogen discharge is demonstrated and benchmarked against prior experimental findings. These tests also include comparisons of three separate models for the scattering angle and their impact on the obtained α/p and mean electron drift velocity. It is found that isotropic scattering combined with restricting the freed electron's scattering angle along the incident electron's velocity vector during ionisation events gives the closest agreement of α/p compared to experimental measurements.

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Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)
2. Plasmaphysik (IEK-4)
3. JARA - HPC (JARA-HPC)

Research Program(s):

1. 5111 - Domain-Specific Simulation & Data Life Cycle Labs (SDLs) and Research Groups (POF4-511) (POF4-511)
2. Kinetic Plasma Simulation with Highly Scalable Particle Codes (jzam04_20190501) (jzam04_20190501)

Appears in the scientific report 2021

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Electronics and Telecommunications Collection ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; National-Konsortium ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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