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Title: On the role of finite grid extent in SOLPS-ITER edge plasma simulations for JET H-mode discharges with metallic wall

Journal Article · · Nuclear Materials and Energy
 [1]; ORCiD logo [1]; ORCiD logo [2];  [3];  [4];  [5]; ORCiD logo [6];  [7];  [7]; ORCiD logo [7];  [1];  [2];  [2];  [8]
  1. Forschungszentrum Juelich (Germany). Inst. fur Energie- und Klimaforschung (IEK)
  2. ITER Organization, St. Paul Lez Durance (France)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. KTH Royal Inst. of Technology, Stockholm (Sweden). Association VR, Fusion Plasma Physics
  5. Aalto Univ., Espoo (Finland)
  6. Univ. de Lisboa (Portugal). Inst. de Plasmas e Fusão Nuclear, IST
  7. Culham Science Centre, Abingdon (United Kingdom). Culham Centre for Fusion Energy (CCFE)
  8. Max-Planck-Inst. für Plasmaphysik, Garching (Germany)

The impact of the finite grid size in SOLPS-ITER edge plasma simulations is assessed for JET H-mode discharges with a metal wall. For a semi-horizontal divertor configuration it is shown that the separatrix density is at least 30% higher when a narrow scrape-off layer (SOL) grid width is chosen in SOLPS-ITER compared to the case for which the SOL grid width is maximised. The density increase is caused by kinetic neutrals being not confined inside the divertor region because of the reduced extent of the plasma grid. In this case, an enhanced level of reflections of energetic neutrals at the low-field side (LFS) metal divertor wall is observed. This leads to a shift of the ionisation source further upstream which must be accounted for as a numerical artefact. An overestimate in the cooling at the divertor entrance is observed in this case, identified by a reduced heat flux decay parameters λqdiv. Otherwise and further upstream the mid-plane heat decay length λq parameter is not affected by any change in divertor dissipation. This confirms the assumptions made for the ITER divertor design studies, i.e. that λq upstream is essentially set by the assumptions for the ratio radial to parallel heat conductivity. It is also shown that even for attached conditions the decay length relations λne > λTe > λq hold in the near-SOL upstream. Thus for interpretative edge plasma simulations one must take the (experimental) value of λne into account, rather than λq, as the former actually defines the required minimum upstream SOL grid extent.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE; Euratom
Grant/Contract Number:
AC05-00OR22725; 633053
OSTI ID:
1648929
Journal Information:
Nuclear Materials and Energy, Vol. 17; ISSN 2352-1791
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 5 works
Citation information provided by
Web of Science

References (14)

Assessment of edge modeling in support of ITER journal August 2011
The new SOLPS-ITER code package journal August 2015
Presentation of the New SOLPS-ITER Code Package for Tokamak Plasma Edge Modelling journal January 2016
Plasma edge and plasma-wall interaction modelling: Lessons learned from metallic devices journal August 2017
SOLPS-ITER Study of neutral leakage and drift effects on the alcator C-Mod divertor plasma journal August 2017
Fuel retention studies with the ITER-Like Wall in JET journal July 2013
Numerical modelling of high density JET divertor plasma with the SOLPS4.2 (B2-EIRENE) code journal September 2008
A study of the perpendicular particle transport properties in the scrape-off layer of ASDEX journal May 1985
Scaling of the tokamak near the scrape-off layer H-mode power width and implications for ITER journal August 2013
Analysis of a multi-machine database on divertor heat fluxes journal May 2012
Simulation of neutral gas flow in the JET sub-divertor journal October 2017
Self-consistent coupling of DSMC method and SOLPS code for modeling tokamak particle exhaust journal May 2017
Neutral pathways and heat flux widths in vertical- and horizontal-target EDGE2D-EIRENE simulations of JET journal July 2018
Finalizing the ITER divertor design: The key role of SOLPS modeling journal December 2011