barbora gulejová 1 of 19 centre de recherches en physique des plasmas swiss physical society...
TRANSCRIPT
Barbora Gulejová Swiss physical society 26/3/2008 1 of 19
Centre de Recherches en Physique des Plasmas
SOLPS5 simulations of
ELMing H-mode
Barbora Gulejová
Richard Pitts, David Coster, Xavier Bonnin,
Roland Behn, Marc Beurskens, Stefan Jachmich,
Jan Horáček, Arne Kallenbach
Barbora Gulejová Swiss physical society 26/3/2008 2 of 19
Centre de Recherches en Physique des Plasmas
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
****
**
Barbora Gulejová Swiss physical society 26/3/2008 3 of 19
Centre de Recherches en Physique des Plasmas
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!
Barbora Gulejová Swiss physical society 26/3/2008 4 of 19
Centre de Recherches en Physique des Plasmas
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 =>
Barbora Gulejová Swiss physical society 26/3/2008 5 of 19
Centre de Recherches en Physique des Plasmas
SScrape-crape-OOff ff LLayer ayer PPlasma lasma SSimulationimulation Suite of codes to simulate transport in edge plasma of tokamaks
B2B2 - 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 5SOLPS 5 – coupled EIRENE + B2.5
Main inputs: * magnetic equilibrium * Psol = Pheat – Prad
core * upstream separatrix density ne
* EELM
Free parameters: cross-field transport coefficients (D┴, ┴, v┴)
B2 plasma background =>recycling fluxes
EIRENE
Sources and sinks due to neutrals and molecules
measured
systematicallyadjusted
Mesh
72 grid cells poloidallyalong separatrix
24 cells radially
D0 D1+ C0 C1+ C2+ C3+ C4+ C5+ C6+
Barbora Gulejová Swiss physical society 26/3/2008 6 of 19
Centre de Recherches en Physique des Plasmas
Type III ELMing H-mode on TCVType III ELMing H-mode on TCVELMs - too rapid (frequency ~ 200 Hz) for comparison on an individual ELM basis => Many similar events are coherently averagedinside 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
tpre ~ 2 ms
telm ~ 100 μs
tpost ~ 1 ms
Post-ELM phasePre-ELM phaseELM = particles and heat are thrown into SOL ( elevated cross-field transport coefficients)
Barbora Gulejová Swiss physical society 26/3/2008 7 of 19
Centre de Recherches en Physique des Plasmas
Pre-ELM and ELM simulation - theoryPre-ELM and ELM simulation - theory
Ddr
dnT
dr
dTn
At
E
ELMELM
ELM ..2
5..
..2
Cross-field radial transport in the main SOL - complex phenomenaAnsatz:( 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 = tELM = 10-4s2.) at poloidal location -> expelled from area AELM at LFS
Cross-field radial transport => approximate estimation of transport parameters during ELM corresponding to the given expelled energy WELM, tELM and AELM
AELM= 1.5m2
W = 600 JD ┴
┴
0
20
20 40
*
Barbora Gulejová Swiss physical society 26/3/2008 8 of 19
Centre de Recherches en Physique des Plasmas
ELM is more convective than conductive !
<Teped>Δ.neped exceeds <neped>Δ .Teped
in the contribution to EELM =>
smaller TB
┴D ┴
TS measurements (R.Behn et al., PPCF 49 (2007)) => larger drop in ne than Te 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 !
AELM=1.5m2 – Gaussian function of multiplicators polloidally
1 ELM cycle of total 400 μs, * 100 μs before ELM
* ELM duration = tELM = 100μs =100 points during ELM event
* 200 μs after ELM
Upstream
Barbora Gulejová Swiss physical society 26/3/2008 9 of 19
Centre de Recherches en Physique des Plasmas
SOLPS < Exp (LP)
factor ~ 1.5
SOLPS >> Exp (coav LP) ( R.Pitts,Nucl.Fusion 43 (2003)) factor ~ 3
Type III TCV ELM simulationDownstream
Barbora Gulejová Swiss physical society 26/3/2008 10 of 19
Centre de Recherches en Physique des Plasmas
Type I ELMing H-mode on JET# 58569 Succesfully modelled by EDGE2D + NIMBUS by Arne Kallenbach (PPCF 46,2004)
Core LIDAREdge LIDAR Li beam ECE
Parameters
Bt = 2 T Ip = 2 MA
ne= 4x1019 m-3
P(SOL)= 12 MW
GAS PUFF from inner divertor !!
ELM parametersfelm ~ 30 HzΔWELM ~ 200 kJ
PIN ~ 14 MW PRAD (core)
Dalpha
Wdia
time
Barbora Gulejová Swiss physical society 26/3/2008 11 of 19
Centre de Recherches en Physique des Plasmas
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.
Barbora Gulejová Swiss physical society 26/3/2008 12 of 19
Centre de Recherches en Physique des Plasmas
Pre-ELM model vs.experimentEDGE2D+NIMBUS SOLPS5
r-rsep [m]
0
22
0.05
Same AnsatzD,Chi,v
Same ne,Te,Tiupstreamprofiles -0.05
Barbora Gulejová Swiss physical society 26/3/2008 13 of 19
Centre de Recherches en Physique des Plasmas
Pre-ELM vs. ELM simulation
0.1
0.05
0.05
EDGE2D+NIMBUS SOLPS5
ELMD x 20
Chi x 401ms
-0.05
0
0
0.05
0.05
-0.05
Barbora Gulejová Swiss physical society 26/3/2008 14 of 19
Centre de Recherches en Physique des Plasmas
Model vs. experiment-targets(LP)EDGE2D+NIMBUS
LP
250
25
5
300
25
7
outer targetinner targetSOLPS5 outer target
r-rsep map2mid
r-rsep map2mid
Barbora Gulejová Swiss physical society 26/3/2008 15 of 19
Centre de Recherches en Physique des Plasmas
Type I ELMing H-mode on JET
# 70224
Wdia
PIN ~ 20 MW PRAD (below Xpoint)
PRAD (core)
Dalpha Parameters
Bt = 3 T Ip = 3 MA
ne=6x1019 m-3
P(SOL)= 19 MW
No GAS PUFF !!
ν*ped ~0.03 -0.08 (expected for ITER!)
ELM parametersfelm ~ 2 HzΔWELM ~ 1 MJ
Simulated for the first time ! … with SOLPS5
Core LIDAREdge LIDAR Li beam HRTS ECE
Langmuir probes
time
=baseline scenario for QDT=10 burning plasma operation on ITER !!! To avoid divertor damage => maximum ΔWELM (ITER) ~ 1MJ (at TCV 0.005 MJ !!!)
= this is achievable on JET
Bolometry (A.Huber)radiation between ELMs
Barbora Gulejová Swiss physical society 26/3/2008 16 of 19
Centre de Recherches en Physique des Plasmas
Core LIDAREdge 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 m2.s-1 in pedestal 1 m2.s-1 in SOLΧ┴= 0.7 m2.s-1 in pedestal 1 m2.s-1 in SOL
(TCV pedestal: D┴= 0.007 m2.s-1 Χ┴= 0.25 m2.s-1 )
ne [m-3]
Te [eV]
vperp [m.s-1]
inward pinch!
D [m2.s-1]Χ [m2.s-1]
Barbora Gulejová Swiss physical society 26/3/2008 17 of 19
Centre de Recherches en Physique des Plasmas
Simulation vs.experiment - targets Outer targetInner target SOLPS LP LP
80
1,2
30
50
0.5
50
r-rsep r-rsep map2mid
r-rsep
r-rsep map2mid
Inner target – good agreement Outer target SOLPS Te too high!
Barbora Gulejová Swiss physical society 26/3/2008 18 of 19
Centre de Recherches en Physique des Plasmas
CONCLUSIONS
Type III ELMing H-mode at TCV andType 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
*
***
**
Barbora Gulejová Swiss physical society 26/3/2008 19 of 19
Centre de Recherches en Physique des Plasmas
Thank you for attention !