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CCIC – 05 Meeting. Field line tracing And 3D scrape-off density profiles. S. Carpentier, R. A. Pitts With thanks to: S. Lisgo, A. Kukushkin (IO/FST/PWI), R. Mitteau (IO/TKM).
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CCIC – 05 Meeting Field line tracing And 3D scrape-off density profiles S. Carpentier, R. A. Pitts With thanks to: S. Lisgo, A. Kukushkin (IO/FST/PWI), R. Mitteau (IO/TKM)
Who: R. A. Pitts, S. Lisgo, A. Kukushkin, M. Shimada, S. Carpentier + external collaborators working directly with the group + master students Current Work Breakdown Structure splits into 6 priority areas: Tritium retention and inventory control Tungsten R&D Heat fluxes to plasma-facing components Erosion and migration Dust production and transport Wall conditioning Small IO team can only address a fraction of the established priorities in-house – rely mostly on working with the larger fusion community: ITPA, EU-PWI-TF, contracts, direct contact with individual research groups Much of the work within the group focused on addressing priority design areas together with longer term R&D issues Two large edge code modelling packages: SOLPS, OSM-DIVIMP-EIRENE IO/FST/PWI group
3D Field line tracing using CASTEM 2de sep FLFS ceiling BSM 11 banana-shaped far SOL region upper ceiling BSM contact points FLFS*-wall BSM 18 outboard BSM (not recessed) BSM log-shape [P.C. Stangeby, R. Mitteau] Reference plasma equilibrium, QDT = 10 burning phase (*FLFS : First Limited Flux Surface) (exaggerated shape)
Connection length profile ∆R < 3cm Calculations recently extended between 2de separatrix and FLFS <Lc> ~ 60 m
Density profiles in the far SOL (1) Outer SOL between 2de sep and FLFS Far SOL (in the shadow of BSM11-18) NB. If Lc = cst ~60 m => λn = [4 – 17] cm [ITER Thermal Loads Specifications, 2009] with: • Assumptions:[ITER Thermal Loads Specifications, 2009] • Enhanced (blobby) convective anomalous transport in the far scrape-off layer • Flat Te, Ti profiles: λT -> ∞ λn ~λq • vSOL = 30-100 m.s-1 at omp • Range of temperature, densities, decay length • Two min/max cases: • High ne, low Te, long decay length • ne = 1.5 1019 m-3, Te=10 eV, Ti = 2.Te • Low ne, high Te, short decay length • ne = 5 1018 m-3, Te=20 eV, Ti = 2.Te
Density profiles in the far SOL (2) High ne, low Te, long decay length ne = 1.5 1019 m-3, Te=10 eV, Ti = 2.Te Low ne, high Te, short decay length ne = 5 1018 m-3, Te=20 eV, Ti = 2.Te Density drop ~ 6cm outside the FLFS 2de sep FLFS Assuming λ = cst = 0.17m Assuming λ = cst = 0.04m r – rsep (m at midplane)
Annex 2de sep FLFS High ne low Te “low” cs vSOL ~ 100 m.s-1 <λn> ~ 0.16m Low ne high Te “high” cs vSOL ~ 30 m.s-1 λn (m) λn FLFS ~ 0.08m <λn> ~ 0.035m λn FLFS ~ 0.03m Radial profile at omp – decay length
Annex Radial profile at omp – connection length
Annex DIVIMP vs CASTEM SOLPS 1st sep 2de sep FLFS Radial profile at omp – connection length SOLPS+DIVIMP (extended grid, poloidal cross-section) CASTEM (3D field line tracing) Good agreement between DIVIMP and CASTEM calculations
Annex Radial profile at omp – connection length previous reference scenario, smooth wall [A.Loarte] SOLPS+DIVIMP CASTEM density drop location
Annex previous reference scenario, smooth wall [A.Loarte] shifted + 4cm Radial profile at omp – connection length SOLPS+DIVIMP CASTEM density drop location
Annex 2de sep at ∆R = 5cm 2de sep at ∆R = 10cm Comparison for: High ne, low Te, long decay length case ne = 1.5 1019 m-3, Te=10 eV, Ti = 2.Te Assuming λ = cst = 0.17m New reference scenario (∆R = 10cm) + Lc calculations with shaped wall previous reference scenario (∆R = 5cm) + Lc calculations with smooth wall Radial profile at omp – density profiles r – rsep (m at midplane)