Docstoc

Folie sublimation

Document Sample
Folie sublimation Powered By Docstoc
					       Benchmarking
       DIVIMP-ERODEPDIF
       ITER predictions on material
       mixing using JET results
       M. Reinelt,
       K. Schmid, K. Krieger

       Max-Planck-Institut für Plasmaphysik
       EURATOM Association, Garching b. München, Germany




SEWG Meeting JET                                           07.07.2009
Outline


          Concepts and status of modeling of
          PWI with DIVIMP (Work in progress!)

           Limits and extensions of DIVIMP

           Standard and extended grids

           Modeling of material mixing

           Status of Be / C calculations for JET

           Short term plans
What is DIVIMP ?

 DIVIMP : "DIVertor IMPurities"
 developed by P.Stangeby / D. Elder (1992)

 Designed for impurity transport in divertor and SOL of tokamaks

       • Simulates (erosion) and impurity transport in plasma boundary

       • Monte Carlo modeling

            ... of particle trajectories through plasma background based on
                forces on impurity atoms
            ... of reactions in the plasma (ionisation, neutralisation, chemistry)
 What is DIVIMP ?
Limitations                                                      Improvements

 • 2D Model (poloidal X-section)                                 -----
                    Toroidal symmetry !
 • Static plasma background                                      -----
                    Impurities are traces !



 • Outer most flux surface from target to target                 Extended grids
                     Gaps between grid and wall                 (S. Lisgo)

 • Impurity generation                                           FluxCalc/ProbCalc
                     No sputtering by multiple plasma species    (K. Schmid)
                     No sputtering at walls (only target)

 • Plasma facing wall                                            ERODEPDIF
                   No multiple wall elements                    (K. Schmid)
                   No wall material mixing
                   No T-dep. effects (Sublimation...)
                   No re-deposition
 What is DIVIMP ?
Limitations                                                      Improvements

 • 2D Model (poloidal X-section)                                 -----
                    Toroidal symmetry !
 • Static plasma background                                      -----
                    Impurities are traces !



 • Outer most flux surface from target to target                 Extended grids
                     Gaps between grid and wall                 (S. Lisgo)

 • Impurity generation                                           FluxCalc/ProbCalc
                     No sputtering by multiple plasma species    (K. Schmid)
                     No sputtering at walls (only target)

 • Plasma facing wall                                            ERODEPDIF
                   No multiple wall elements                    (K. Schmid)
                   No wall material mixing
                   No T-dep. effects (Sublimation...)
                   No re-deposition
Conceptual approach
Materials           OEDGE            SOLPS                CARRE,
properties          (OSM)          (B2+Eirene)          recent codes
databases                     Codes for "plasma side"


                    DIVIMP




               ERODEPDIF /
      Codes for
              Analytical models
      "material side"


  SDTrim           FluxCalc
                   ProbCalc
Conceptual approach
Materials              OEDGE                SOLPS                  CARRE,
                                                          Grid
properties             (OSM)              (B2+Eirene)            recent codes
databases

                   Background plasma


                       DIVIMP
• Diffusion
• Sublimation
                                                Expected results:
                   Re-deposition matrix         * Steady state wall
                   for each element
                                                  concentrations &
                                                  erosion fluxes
                   ERODEPDIF /
                   Analytical models            * Plasma impurity
                                                  concentrations
Phys. sputtering   Impurity generation


   SDTrim             FluxCalc
                      ProbCalc
Conceptual approach
Materials              OEDGE                SOLPS                CARRE,
                                                        Grid
properties             (OSM)              (B2+Eirene)          recent codes
databases

                   Background plasma


                       DIVIMP
• Diffusion
• Sublimation
                   Re-deposition matrix
                   for each element


                   ERODEPDIF /
                   Analytical models


Phys. sputtering   Impurity generation


   SDTrim             FluxCalc
                      ProbCalc
Conceptual approach
Materials              OEDGE                SOLPS                CARRE,
                                                        Grid
properties             (OSM)              (B2+Eirene)          recent codes
databases

                   Background plasma


                       DIVIMP
• Diffusion
• Sublimation
                   Re-deposition matrix
                   for each element


                   ERODEPDIF /
                   Analytical models


Phys. sputtering   Impurity generation


   SDTrim             FluxCalc
                      ProbCalc
  Extended grid (EG)




        JET SG            JET EG [1]
        (Standard grid)   (Extended grid)




[1] By S. Lisgo
Extended grid (EG)
Conceptual approach
Materials             OEDGE                 SOLPS                CARRE,
                                                        Grid
properties         (SOL22 option)         (B2+Eirene)          recent codes
databases

                   Background plasma


                       DIVIMP
• Diffusion
• Sublimation
                   Re-deposition matrix
                   for each element


                   ERODEPDIF /
                   Analytical models


Phys. sputtering   Impurity generation


   SDTrim             FluxCalc
                      ProbCalc
  ERODEPDIF
  Treat komplex plasma-wall interactions and material evolution in a simplified way



 ERODEPDIF [2]:
       Looks iteratively for a flux balance solution
       No time evolution




[2] K. Schmid, Nucl. Fusion 48 (2008) p. 105004
  ERODEPDIF
  Treat komplex plasma-wall interactions and material evolution in a simplified way



 ERODEPDIF [2]:
         Looks iteratively for a flux balance solution
         No time evolution
                                                   Be-evaporation
 JET experimental data [3]:
 Integrated Be flux
 from e.g. outer divertor                                              wall gap
 from Be II (527nm)                                              L-mode high
                                                                 L-mode low
                                                                 H-mode low




[2] K. Schmid, Nucl. Fusion 48 (2008) p. 105004
[3] K. Krieger et al, J. Nucl. Mat. 390–391 (2009) p. 110
  New analytical model
  Treat komplex plasma-wall interactions and material evolution in a simplified way


 Newly developed analytical model [4]:


  Background                                  Reaction                    Bulk
  plasma                                      zone




[4] Concept and implementation by K. Schmid, Nucl. Techn., 159/3, 2007, p. 238
  New analytical model
  Treat komplex plasma-wall interactions and material evolution in a simplified way

                                    Net deposition:
                                    Layer growth



    BGP            Be, C, D, He, Ar                Reaction          Be, C        Bulk, z.B. C
    D, He, Ar                                      zone
                            Be, C                                       C

                                    Net erosion

                                             * Constant thickness            * Variable thickness
                                             * Variable composition          * Constant composition
                                                  (but homogeneous
                                                  distribution)




[4] Concept and implementation by K. Schmid, Nucl. Techn., 159/3, 2007, p. 238
  New analytical model
  Treat komplex plasma-wall interactions and material evolution in a simplified way

                                    Net deposition:
                                    Layer growth



    BGP            Be, C, D, He, Ar                Reaction          Be, C        Bulk, z.B. C
    D, He, Ar                                      zone
                            Be, C                                       C

                                    Net erosion

   Applicable to “simple”                    * Constant thickness            * Variable thickness
    systems like Be & C                      * Variable composition          * Constant composition
                                                  (but homogeneous
     YPartial ~ C*YTotal                          distribution)




[4] Concept and implementation by K. Schmid, Nucl. Techn., 159/3, 2007, p. 238
  New analytical model

                                               Reaction                 Bulk
                                               zone
              Plasma




   First wall is subdivided into n-tiles

    Each tile receives a flux due to erosion & re-deposition from other tiles
    Plasma transport is characterized by a re-deposition matrix:



    Flux of material m on tile i:

   Solved as a 4n coupled differential equation system in Mathematica

                       RESULT: Time evolution of the first wall !

[4] Concept and implementation by K. Schmid, Nucl. Techn., 159/3, 2007, p. 238
Prove Of Principle of solver
First (simple)     • 7 Wall tiles
                   • Constant D plasma flux in the range of 1022 m-2 s-1
test case:         • Be & C erosion yields in % range
                   • Very simplified plasma transport (exp. distance decay)
Initially pure C

                                                   #4 eroded        Be buried by
                                                                    re-dep. C




                                 Be re-deposition
Conceptual approach
Materials             OEDGE                 SOLPS                CARRE,
                                                        Grid
properties         (SOL22 option)         (B2+Eirene)          recent codes
databases

                   Background plasma


                       DIVIMP
• Diffusion
• Sublimation
                   Re-deposition matrix
                   for each element


                   ERODEPDIF /
                   Analytical models


Phys. sputtering   Impurity generation


   SDTrim             FluxCalc
                      ProbCalc
Concept: Re-deposition matrix by DIVIMP




        static BGP
                     static BGP      Lauch flux of
                                     Be impurity ions
                                     and map points of
                                     re-deposition
                                     (Charge resolved)
                        Bin

                           Re-deposition matrix
Re-deposition matrix (JET SG)
Re-deposition matrix (JET SG)
                                Promt
                                re-deposition




             ...   ...   ...
Re-deposition matrix (JET SG)
Re-deposition matrix (JET SG)

                                Most Be is re-deposited
                                at the inner taget
Short term plans

Experimental data (K. Krieger)

             Validation


JET                                                ITER
                                   Extrapolation
   SG + EG (Partly done)                             SG (Previously done) + EG
   Be + C                                            Be migration (+ W Divertor)
   Background plasma: OEDGE,                         Background plasma: OEDGE
    Experimental + Extrapolation



                 1) Get EG and OEDGE running for both JET and ITER
                 2) Obtain re-deposition matrices for
                           JET: Be, C       ITER: Be, W
                 3) Compare SG and EG based calculations
                 4) Investigate the steady state wall compositions
                    and impurity plasma concentrations
 What is DIVIMP ?

Modelling framework:


                       SOLPS 4.0 (5.0)
CARRE (SONNET)
2D Grid generator:       B2 (B2.5)        EIRENE (MC)
Plasma current           Fluid code       Neutral transport
Magnetic field           B. Braams, NY    (Reiter, FZJ)




                        OEDGE            EIRENE (MC)          DIVIMP (MC):
                        Onion skin       Neutral transport    Impurity transport
                        model            (Reiter, FZJ)        (Stangeby, Toronto)




                        EDGE2D           NIMBUS
Grid
       Standard grid (SG)                            Grid extension to match the
       directly from B2/Eirene:                      vessel geometry,
                                                     so far manually customized
       + PWI  Interpolation of plasma
       parameters to the wall
       (lack of physics: linear)

       Overestimation of flux
?      into divertor !




                       Free gird (w/o cut with neutral wall)
                       is modified by DIVIMP
                       (requires a lot of manual input,
                       automatic generation in progress)
Standard grids : ITER (Divertor)

Background                    Unrolled data structure:
plasma
                              SOL        Flux Surfaces




                   Divertor




                                                             Divertor
                                    Separatrix

                                    Core Plasma




                              SOL




                                                  Divertor
Standard grids : ITER (Divertor)

Background                    Unrolled data structure (B2-EIRENE):
plasma
                                    SOL         Flux Surfaces




                   Divertor




                                                                     Divertor
                                           Separatrix
                                          Core Plasma
Impurity transport




                                                              Reflection, Deposition
                     Anomal diffusion ┴ B




                                                              Wall / Divertor:
                                            Ionisation
                                            Recombination
                                            Thermalisation




                                   Classic transport || B
                                   (gyro center motion)
                                   • Friction force
                                   • Thermal gradient force
                                   • Electric force
 What is FluxCalc / ProbCalc ?

       Problem: Impurity generation by impurities (Self sputtering of W !)



• Background plasma                                     For every wall element:
• Grid                                                  • Te, Ti
• Ion fluxes at grid edge
                                   FluxCalc             • Ion flux (D, He, C)
• CX-Flux at grid edge                                  • CX-flux
• Neutral wall                                            (Energy & angle resolved)



SDTrim (parameterized)           Sputteryields                   ProbCalc



                                                        For every wall element:
     ERODEPDIV +                                        • Erosion flux
  Redeposiotionmatrix                                   • Absolute wall launch
                                                          probabilities of impurities
Summary



     Latest DIVIMP version (6 revision 41) working

     Modifications for coupling with ERODEPDIF

     Ability to calculate re-distribution matrices (Be for JET SG)

     Analytical solution for Be/C JET cases

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:6
posted:7/19/2011
language:English
pages:38