SOLEDGE2D-EIRENE modelling for preparing WEST divertor operation - - PowerPoint PPT Presentation
SOLEDGE2D-EIRENE modelling for preparing WEST divertor operation G. Ciraolo, H. Bufferand, Ph. Ghendrih, J. Bucalossi , Y. Marandet, J. Denis, N. Fedorczak, D. Galassi, J. Gunn, R. Leybros, B. Pgouri, E. Serre, P. Tamain 28th MAY
| PAGE 1 28th MAY 2015
Bucalossi , Y. Marandet, J. Denis, N. Fedorczak, D. Galassi, J. Gunn, R. Leybros, B. Pégourié, E. Serre, P. Tamain
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Divertor configuration Limiter configuration
WEST
ITER/6
Divertor coil Divertor coil Stabilizing plate Stabilizing plate Carbon environment Tungsten environment
A major upgrade for investigating: H mode physics Tungsten environment Taking full benefit from Tore Supra assets Long pulse physics and operation
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2D transport code developed in parallel to 3D turbulent code TOKAM3X Multi-species plasma solver coupled to EIRENE for neutrals
Solves equations for densities, parallel velocities, temperatures and electric potential Drifts velocity are being implemented
Example of SOLEDGE2D-EIRENE simulations for WEST geometry
1.
WEST H mode plasmas:
How to choose reasonable radial transport coefficients for SolEdge2D simulations?
to present experiments (example on an ASDEX H mode discharge)
SOLEDGE. 2. WEST long pulse requirements
| PAGE 4 Modelling the plasma up to the wall in the divertor as well as in the main chamber region
Neutral pressure
setting cross field transport coefficients: the standard approach
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Based on a well documented deuterium H-mode plasma in AUG Carbon wall (sputtered radiator) / Sputtering yield adjusted to match experimental SOL radiated power Transport parameters from [A. Chankin et al., PPCF 48 (2006)] found to match OMP experimental profiles SOLEDGE2D-EIRENE simulation results in the
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High recycling divertor solution Good agreement between simulation and experiment on target parameters
| PAGE 7 Same transport coefficients as in the AUG case
Tungsten wall: C sputtering replaced by Nitrogen seeding
Nitrogen puff Outboard Mid Plane Outer strike point
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more generally on plasma behavior in the divertor region Examples of radial profiles for transport coefficients Can we find a way to obtain transport radial coefficient from a more « first principle » approach ?
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Reynolds Averaged Navier-Stokes (RANS) approach:
Reynolds tensor
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Courtesy SimScale
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Test case for the model: MISTRAL base case on Tore Supra Comparison with experiment by J. Gunn et al., J. Nucl. Mat. 363-365 (2007)] evidence of transport enhancement on the LFS Ohmic plasmas. Plasma-wall contact point moved around the vessel
HFS BOT LFS TOP
| PAGE 14 HFS BOT LFS TOP The 4 configurations are simulated with SOLEDGE2D-EIRENE coupled with the turbulence model Spontaneous ballooned diffusion coefficients enhanced turbulence intensity in the outboard midplane (interchange instable side)
| PAGE 15 HFS BOT LFS TOP
The 4 configurations are simulated with SOLEDGE2D-EIRENE coupled with the turbulence model Spontaneous ballooned diffusion coefficients enhanced turbulence intensity in the outboard midplane (interchange instable side)
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HFS BOT LFS TOP The 4 configurations are simulated with SOLEDGE2D-EIRENE coupled with the turbulence model
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L a n g m u i r p r
e s i m u l a t i
s
Reasonable agreement for Mach number flow reversal Difference in density: decay less pronounced in the simulation
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WEST long pulse requirements
| PAGE 19 Access to plasma behavior all along the wall:
28th MAY 2015 | PAGE 20
| PAGE SolEdge-EIRENE adapted to simulate an arbitrary number of ions For every ion the following equations are solved: Mass balance Momentum balance Energy balance (also solved for electrons) with Coupling terms Atomic physics ( )
n
S v b u n t n
α α α α α
= + ⋅ ∇ + ∂ ∂ ) (
pinch
v n n D v + ∇ − =
⊥ α α α
( )
( )
( )
nu
S R b u u n m E q T n v b u u n m t u n m
α α α α α α α α α α α α α α α α α
ν ν + + ∇ + ∇ ⋅ ∇ + + − ∇ = + ⋅ ∇ + ∂ ∂
⊥ ⊥
// // // //
) (
α
α α α α α α α α α α α α α α α α α α α α α α α α α α α
ν κ χ ν
E
S Q u R b h u T T n u n u E q v b u u n m v b u T n u n m T n t + + + − ∇ + ∇ ⋅ ∇ + ∇ + ∇ ⋅ ∇ + = + + + ⋅ ∇ + + ∂ ∂
⊥ ⊥ ⊥
2 // // // 2 // 2 2
2 1 2 1 ) ( 2 1 ) ( 2 5 2 1 2 3
24th NOVEMBRE 2014 | PAGE Coupling terms come from collisions between the different particles Example: effect of collisions in momentum balance A closure for these terms has been derived by Braginskii (1965) only for a two species ion-electron plasma. Expression for these terms have been inferred on heuristic basis from Braginskii’s work (Braams work for SOLPS - 1987) Ongoing work to express these terms from theoretical closure (Zhdanov, Rozhanski)
§ Thermal force: § Friction force
Drive impurity flows from cold to hot areas (contamination) Impurities follow the plasma flow toward the wall (flushing)
≠
α β αβ αβ α u T
β αβ α αβ αβ
// ) 2 ( // ) 1 (
β α αβ αβ
) 3 (
24th NOVEMBRE 2014 | PAGE Equations checked with the Method of Manufactured Solutions (MMS): Check if the code solves the equation that it claims to solve Tests are run automatically when the code is modified non-regression tests Atomic physics are being checked testing ionization- recombination equilibrium in a very simple domain geometry (no transport) Optimization effort to reduce computation time (G. Latu, C. Passeron) Ionization/recombination equilibrium for Carbon
C+ C2+ C3+ C4+ C5+ C6+
Transport diffusivities have been determned by Chankin to match midplane experimental measurements with SOLPS results. Procedure: Use the same transport parameters and repeat the simulation with SOLEDGE – Attempt to use the same code settings (as far as possible)
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SOLEDGE grid
110 x 180
Full line with markers: SOLPS Dashed lines: SOLEDGE 18 x 48
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Target profiles comparison: heat flux
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Target profiles comparison: probe data
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SOLPS results: 2.7MW with drifts
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Divertor: a crucial component for power exhaust
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WEST: risk minimization in support to ITER divertor strategy ITER divertor heat loads specs: Steady state: 10 MW/m2 Slow transients: 20 MW/m2 ELMs - disruptions
Optimization of industrial scale production / qualification processes ahead of ITER divertor procurement Assessment of power handling capabilities / lifetime of ITER high heat flux tungsten divertor components in tokamak environment Validated scheme for protection of actively cooled metallic plasma facing components
Demonstration of integrated long pulse H mode scenario (optimization of RF heating, control of tungsten contamination and plasma density) Investigation of advanced scenario regimes (fully non inductive H mode operation, highly radiating scenario, …)
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Full-W
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Carbon environment
Bumper
CFC/W-coating
Lower target
“ITER Technologies” Water cooled Stainless Steel panel
Baffle
Cu/W-coating
VDE/ripple protection
Cu/W-coating
Upper target
Cu/W-coating
up to 8 MW/m2
(steady-state / double null)
up to 3 MW/m2 (steady-state)
* 10 MW/m2 in steady state 20 MW/m2 in slow transient ( < 10s)
ITER requirement* (and beyond)
Antenna Limiters
CFC/W-coating
A flexible configuration: lower, upper and double null configuration
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Soledge2D: Plasma transport from r/a ≈0.8 to sheath entrance Tables from PIC code: Acceleration of ions in the sheath TRIM: Reflection properties depending on wall material EIRENE: Neutral transport and interactions Quasi-neutral plasma Sheath Wall Neutrals ni, ui, Ti, Te Angle of incidence Rn, RE Sn, SE
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