1. Barbora Gulejová 1 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 SOLPS5 simulations of ELMing H-mode Barbora Gulejová Richard Pitts, David Coster, Xavier Bonnin, Roland Behn, Marc Beurskens, Stefan Jachmich, Jan Horáček, Arne Kallenbach

2. Barbora Gulejová 2 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 OUTLINE SOLPS 5 code package ELM simulation - theory Simulation of Type III ELM at TCV Simulation of Type I ELMing H-mode at JET Code - experiment benchmark Code - code benchmark * * * * * *

3. Barbora Gulejová 3 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 ELMing H-mode = baseline scenario for plasma operation on ITER! Edge localised mode (ELM) Edge localised mode (ELM) H-mode Edge MHD instabilities Periodic bursts of particles and energy into the SOL ELM leaves edge pedestal region in the form of a helical filamentary structure localised in the outboard midplane region of the poloidal cross-section Danger: divertor targets and main walls erosion first wall power deposition Energy stored in ELMs: TCV 500 J JET 200kJ ITER ~ 1-10 MJ => unacceptable MOTIVATION Understanding of the ELM from formation to point of interaction with plasma facing components = Important research goal!

4. Barbora Gulejová 4 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 SOLPS5 modelling of ELMing H-mode Type III & Type I ELMing H-mode TCV & JET benchmark SOLPS & EDGE2D/NIMBUS 1.) 2.a) 2.b) * contribute to understanding transport in the SOL : transient events => ELMs * interpretative modeling of both 1.) steady state and 2.) transient particle and heat fluxes during ELMing H-mode employing the SOLPS5 fluid/Monte Carlo code * rigorous benchmarking = seeking the possible agreement between 1.) experiment and simulation 2.) code and different code MODEL: tool to understand and predict phenomena =>

5. Barbora Gulejová 5 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Scrape-Off Layer Plasma Simulation Suite of codes to simulate transport in edge plasma of tokamaks B2 B2 - solves 2D multi-species fluid equations on a grid given from magnetic equilibrium EIRENE EIRENE - kinetic transport code for neutrals based on Monte - Carlo algorithm SOLPS 5 SOLPS 5 – coupled EIRENE + B2.5 Main inputs: * magnetic equilibrium * P sol = P heat – P rad core * upstream separatrix density n e * E ELM Free parameters: cross-field transport coefficients (D,, v ) B2 plasma background => recycling fluxes EIRENE Sources and sinks due to neutrals and molecules measured systematically adjusted Mesh 72 grid cells poloidally along separatrix 24 cells radially D 0 D 1+ C 0 C 1+ C 2+ C 3+ C 4+ C 5+ C 6+

6. Barbora Gulejová 6 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Type III ELMing H-mode on TCV Type III ELMing H-mode on TCV ELMs - too rapid (frequency ~ 200 Hz) for comparison on an individual ELM basis => Many similar events are coherently averaged inside interval with reasonably periodic elms Time-dependent ELM simulation * starting from time-dependent pre-ELM steady state simulation * equal time-steps for kinetic and fluid parts of code, dt = 10 -6 s t pre ~ 2 ms t elm ~ 100 μs t post ~ 1 ms Post-ELM phasePre-ELM phase ELM = particles and heat are thrown into SOL ( elevated cross-field transport coefficients)

7. Barbora Gulejová 7 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Pre-ELM and ELM simulation - theory Cross-field radial transport in the main SOL - complex phenomena Ansatz:( D,, v ) – variation : * Pure diffusion: v =0 everywhere * More appropriate: Convection simulations with D = D class 2 approaches radially – transport barrier (TB) poloidally – no TB in div.legs Instantaneous increase of the cross-field transport parameters D,, v ! Simulation of ELM 1.) for ELM time – from experiment coh.averaged ELM = t ELM = 10 -4 s 2.) at poloidal location -> expelled from area A ELM at LFS Cross-field radial transport => approximate estimation of transport parameters during ELM corresponding to the given expelled energy W ELM, t ELM and A ELM A ELM = 1.5m 2 W = 600 J D 0 20 40 *

8. Barbora Gulejová 8 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 ELM is more convective than conductive ! Δ.ne ped exceeds Δ.Te ped in the contribution to E ELM => smaller TB D TS measurements (R.Behn et al., PPCF 49 (2007)) => larger drop in n e than T e at the pedestal top => SOLPS : D increased more then during the ELM 100 times 10 times (2 times in SOL) + change of radial shape ! ETB collapse! Type III TCV ELM simulation Very good agreement ! A ELM =1.5m 2 – Gaussian function of multiplicators polloidally 1 ELM cycle of total 400 μs, * 100 μs before ELM * ELM duration = t ELM = 100μs =100 points during ELM event * 200 μs after ELM Upstream

9. Barbora Gulejová 9 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 SOLPS < Exp (LP) factor ~ 1.5 SOLPS >> Exp (coav LP) ( R.Pitts,Nucl.Fusion 43 (2003)) factor ~ 3 Type III TCV ELM simulation Downstream

10. Barbora Gulejová 10 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Type I ELMing H-mode on JET # 58569 Succesfully modelled by EDGE2D + NIMBUS by Arne Kallenbach (PPCF 46,2004) Core LIDAR Edge LIDAR Li beam ECE Parameters B t = 2 T I p = 2 MA n e = 4x10 19 m -3 P(SOL)= 12 MW GAS PUFF from inner divertor !! ELM parameters f elm ~ 30 Hz ΔW ELM ~ 200 kJ P IN ~ 14 MW P RAD (core) D alpha W dia time

11. Barbora Gulejová 11 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Benchmarking code-code SOLPS 5 B2.5 + EIRENE fluid (Braginskii) kinetic (Monte Carlo), neutrals EDGE2D + NIMBUS fluid (Braginskii) kinetic (Monte Carlo), neutrals (less complex then EIRENE!) vs.

12. Barbora Gulejová 12 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Pre-ELM model vs.experiment EDGE2D+NIMBUS SOLPS5 r-r sep [m] 0 2 2 0.05 Same Ansatz D,Chi,v Same ne,Te,Ti upstream profiles -0.05

13. Barbora Gulejová 13 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Pre-ELM vs. ELM simulation 0.1 0.05 EDGE2D+NIMBUS SOLPS5 ELM D x 20 Chi x 40 1ms -0.05 0 0 0.05 -0.05

14. Barbora Gulejová 14 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Model vs. experiment-targets(LP) EDGE2D+NIMBUS LPLP 250 25 5 300 25 7 outer targetinner target SOLPS5 outer target r-r sep map2mid

15. Barbora Gulejová 15 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Type I ELMing H-mode on JET # 70224 W dia P IN ~ 20 MW P RAD (below Xpoint) P RAD (core) D alpha Parameters B t = 3 T I p = 3 MA n e =6x10 19 m -3 P(SOL)= 19 MW No GAS PUFF !! ν* ped ~0.03 -0.08 (expected for ITER!) ELM parameters f elm ~ 2 Hz ΔW ELM ~ 1 MJ Simulated for the first time ! … with SOLPS5 Core LIDAR Edge LIDAR Li beam HRTS ECE Langmuir probes time =baseline scenario for Q DT =10 burning plasma operation on ITER !!! To avoid divertor damage => maximum ΔW ELM (ITER) ~ 1MJ (at TCV 0.005 MJ !!!) = this is achievable on JET Bolometry (A.Huber) radiation between ELMs

16. Barbora Gulejová 16 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Core LIDAR Edge LIDAR Li beam HRTS ECE Simulation vs. experiment - upstream First results for pre-ELM * quite promising * unlike for TCV inward pinch radial profile necessary!! D = 0.01 m 2.s -1 in pedestal 1 m 2.s -1 in SOL Χ = 0.7 m 2.s -1 in pedestal 1 m 2.s -1 in SOL (TCV pedestal: D = 0.007 m 2.s -1 Χ = 0.25 m 2.s -1 ) n e [m -3 ] T e [eV] v perp [m.s -1 ] inward pinch! D [m 2.s -1 ] Χ [m2.s-1]

17. Barbora Gulejová 17 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Simulation vs.experiment - targets Outer targetInner target SOLPS LP 80 1,2 30 50 0.5 50 r-r sep r-r sep map2mid r-r sep r-r sep map2mid Inner target – good agreement Outer target SOLPS Te too high!

18. Barbora Gulejová 18 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 CONCLUSIONS Type III ELMing H-mode at TCV and Type I ELMing H-mode at JET have been succesfully simulated by SOLPS5 both steady state and transient event Agreement obtained between : code - experiment code - code * * * * * *

19. Barbora Gulejová 19 of 19 Centre de Recherches en Physique des Plasmas Swiss physical society 26/3/2008 Thank you for attention !