Plasma edge and plasma-wall interaction modelling: Lessons learned from metallic devices

S. Wiesen, M. Groth, M. Wischmeier, S. Brezinsek, A. Jarvinen, F. Reimold, L. Aho-Mantila

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)

Abstract

Robust power exhaust schemes employing impurity seeding are needed for target operational scenarios in present day tokamak devices with metallic plasma-facing components (PFCs). For an electricity-producing fusion power plant at power density Psep/R > 15 MW/m divertor detachment is a requirement for heat load mitigation. 2D plasma edge transport codes like the SOLPS code as well as plasma-wall interaction (PWI) codes are key to disentangle relevant physical processes in power and particle exhaust. With increased quantitative credibility in such codes more realistic and physically sound estimates of the life-time expectations and performance of metallic PFCs can be accomplished for divertor conditions relevant for ITER and DEMO. An overview is given on the recent progress of plasma edge and PWI modelling activities for (carbon-free) metallic devices, that include results from JET with the ITER-like wall, ASDEX Upgrade and Alcator C-mod. It is observed that metallic devices offer an opportunity to progress the understanding of underlying plasma physics processes in the edge. The validation of models can be substantially improved by eliminating carbon from the experiment as well as from the numerical system with reduced degrees of freedom as no chemical sputtering from amorphous carbon layers and no carbon or hydro-carbon transport are present. With the absence of carbon as the primary plasma impurity and given the fact that the physics of the PWI at metallic walls is less complex it is possible to isolate the crucial plasma physics processes relevant for particle and power exhaust. For a reliable 2D dissipative plasma exhaust model these are: cross-field drifts, complete kinetic neutral physics, geometry effects (including main-chamber, divertor and sub-divertor structures), SOL transport reflecting also the non-diffusive nature of anomalous transport, as well as transport within the pedestal region in case of significant edge impurity radiation affecting pedestal pressure and hence Psep.

Original languageEnglish
Pages (from-to)3-17
Number of pages15
JournalNuclear Materials and Energy
Volume12
DOIs
Publication statusPublished - 1 Aug 2017
MoE publication typeA1 Journal article-refereed

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lessons learned
Beam plasma interactions
Plasmas
carbon
metallic plasmas
interactions
Carbon
plasma physics
Physics
impurities
Facings
tokamak devices
Impurities
physics
power plants
inoculation
electricity
detachment
Tokamak devices
radiant flux density

Cite this

Wiesen, S. ; Groth, M. ; Wischmeier, M. ; Brezinsek, S. ; Jarvinen, A. ; Reimold, F. ; Aho-Mantila, L. / Plasma edge and plasma-wall interaction modelling : Lessons learned from metallic devices. In: Nuclear Materials and Energy. 2017 ; Vol. 12. pp. 3-17.
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Plasma edge and plasma-wall interaction modelling : Lessons learned from metallic devices. / Wiesen, S.; Groth, M.; Wischmeier, M.; Brezinsek, S.; Jarvinen, A.; Reimold, F.; Aho-Mantila, L.

In: Nuclear Materials and Energy, Vol. 12, 01.08.2017, p. 3-17.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Plasma edge and plasma-wall interaction modelling

T2 - Lessons learned from metallic devices

AU - Wiesen, S.

AU - Groth, M.

AU - Wischmeier, M.

AU - Brezinsek, S.

AU - Jarvinen, A.

AU - Reimold, F.

AU - Aho-Mantila, L.

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N2 - Robust power exhaust schemes employing impurity seeding are needed for target operational scenarios in present day tokamak devices with metallic plasma-facing components (PFCs). For an electricity-producing fusion power plant at power density Psep/R > 15 MW/m divertor detachment is a requirement for heat load mitigation. 2D plasma edge transport codes like the SOLPS code as well as plasma-wall interaction (PWI) codes are key to disentangle relevant physical processes in power and particle exhaust. With increased quantitative credibility in such codes more realistic and physically sound estimates of the life-time expectations and performance of metallic PFCs can be accomplished for divertor conditions relevant for ITER and DEMO. An overview is given on the recent progress of plasma edge and PWI modelling activities for (carbon-free) metallic devices, that include results from JET with the ITER-like wall, ASDEX Upgrade and Alcator C-mod. It is observed that metallic devices offer an opportunity to progress the understanding of underlying plasma physics processes in the edge. The validation of models can be substantially improved by eliminating carbon from the experiment as well as from the numerical system with reduced degrees of freedom as no chemical sputtering from amorphous carbon layers and no carbon or hydro-carbon transport are present. With the absence of carbon as the primary plasma impurity and given the fact that the physics of the PWI at metallic walls is less complex it is possible to isolate the crucial plasma physics processes relevant for particle and power exhaust. For a reliable 2D dissipative plasma exhaust model these are: cross-field drifts, complete kinetic neutral physics, geometry effects (including main-chamber, divertor and sub-divertor structures), SOL transport reflecting also the non-diffusive nature of anomalous transport, as well as transport within the pedestal region in case of significant edge impurity radiation affecting pedestal pressure and hence Psep.

AB - Robust power exhaust schemes employing impurity seeding are needed for target operational scenarios in present day tokamak devices with metallic plasma-facing components (PFCs). For an electricity-producing fusion power plant at power density Psep/R > 15 MW/m divertor detachment is a requirement for heat load mitigation. 2D plasma edge transport codes like the SOLPS code as well as plasma-wall interaction (PWI) codes are key to disentangle relevant physical processes in power and particle exhaust. With increased quantitative credibility in such codes more realistic and physically sound estimates of the life-time expectations and performance of metallic PFCs can be accomplished for divertor conditions relevant for ITER and DEMO. An overview is given on the recent progress of plasma edge and PWI modelling activities for (carbon-free) metallic devices, that include results from JET with the ITER-like wall, ASDEX Upgrade and Alcator C-mod. It is observed that metallic devices offer an opportunity to progress the understanding of underlying plasma physics processes in the edge. The validation of models can be substantially improved by eliminating carbon from the experiment as well as from the numerical system with reduced degrees of freedom as no chemical sputtering from amorphous carbon layers and no carbon or hydro-carbon transport are present. With the absence of carbon as the primary plasma impurity and given the fact that the physics of the PWI at metallic walls is less complex it is possible to isolate the crucial plasma physics processes relevant for particle and power exhaust. For a reliable 2D dissipative plasma exhaust model these are: cross-field drifts, complete kinetic neutral physics, geometry effects (including main-chamber, divertor and sub-divertor structures), SOL transport reflecting also the non-diffusive nature of anomalous transport, as well as transport within the pedestal region in case of significant edge impurity radiation affecting pedestal pressure and hence Psep.

U2 - 10.1016/j.nme.2017.03.033

DO - 10.1016/j.nme.2017.03.033

M3 - Article

AN - SCOPUS:85016571978

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JO - Nuclear Materials and Energy

JF - Nuclear Materials and Energy

SN - 2352-1791

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