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第16回 ITPA（SOL/DIV）の概要（ITER divertor strategy, W melting,W fuzz, W HHF testing)
上田良夫（大阪大学）	
PWI 合同研究会
平成24年 7月23日- 24日
筑波大学プラズマ研究センターシンポジューム	プラズマ物理クラスター スクレープオフ層とダイバー タ物理サブクラスター(第1回会合)
炉工学クラスター ブランケット サブクラスター(第2回会合)
双方向型共同研究会合「ガンマ１０装置における炉壁材料の損耗・再堆積の研究とそのダイバータ開発戦略における位置づけ」	

January 18 (Wed)-19 (Thu)	
Chair -E. Tsitrone

Update on ITER / JET
R. Pitts

Tungsten melting
experiments
J. Coenen
B. Lipschultz
B. Basylev

Tungsten fuzz
G Wright
G de Temmerman

Tungsten HHF testing
H. Greuner
E. Tsitrone
G de Temmerman
J. Linke

ITER divertor strategy
Chair A. Kallenbach
W melt experiments in AUG and Textor
C-mod results on W melting
Modeling of W melting experiments and extrapolation
for ITER
Chair Y. Ueda
W fuzz in Alcator C-Mod and comparison of the role ofHe with linear devices
Behavior of a helium-modified (fuzzy) surface duringtransients
Chair Y. Ueda
Damage studies on different W grades with GLADISHHF testing of ITER components
Tungsten damage under simultaneous steady-state
and transient loads
Damage threshold for W under ELM-like thermal loads

各セッションのまとめ	
o ITER divertor strategyn ITERのWダイバータ検討の現状o Tungsten Meltingn TEXTORやAUGでの、リーディングエッジの溶融実験（後述）n C-ModにおけるWタイル溶融層の挙動とプラズマへの影響

o Tungsten Fuzzn C-ModにおけるFuzz生成実験→Fuzz様表面が閉じ込め装置で形成された（後述）n Pilot-PSIによるFuzzの形成とパルス熱負荷影響o あるエネルギー以上のELM様熱パルスで消失（W放出なし）

o Tungsten HHF Testing
nn
n
n

GLADIS（イオンビーム装置）照射によるWの表面状態変化
EUが行ったHHFの熱負荷試験の結果（後述）
定常＋ELM様プラズマパルスによる異常損耗（後述）
電子ビームによるELM様熱パルス繰り返し照射効果のまとめ

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Tungsten nano-tendril growth in theAlcator C-Mod Divertor and the roleof He!
G.M. Wright, D. Brunner, B. LaBombard, B. Lipschultz, J.L. Terry,and D.G. Whyte"
Plasma Science & Fusion Center, MIT, Cambridge USA""

G.M. Wright, ITPA, Aachen-Juelich, 01/2012	

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Tungsten probe reached and exceededsurface temperatures required for fuzz growth!

Bubble regime!

Nano-tendril!
growth regime!

W probe ramped ~11o into parallel
heat flux and is electrically/thermallyisolated. Mo tiles are grounded andramped at ~2o""èW probe intercepts significantly
more parallel heat flux and rapidly
reaches higher surfacetemperatures."
Surface heat flux is obtained
directly from probe measurements.
W probe Tsurf is determined from 1D heat flux modeling. Mo tiles Tsurf
determined with IR thermography"

Note: Surface continues to be modified at Tsurf > 2000 K but the morphology changes "G.M. Wright, ITPA, Aachen-Juelich, 01/2012	

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Nano-tendrils are fully formed on surfaceof the tungsten probe exposed to heat
fluxes of 30-40 MW/m2!
After exposure!
Mo ramped tiles"
W Probe""Thickness of individual tendril
is 50-100 nm, which is thicker
than tendrils grown in linear
devices (20-30 nm)"

G.M. Wright, ITPA, Aachen-Juelich, 01/2012	

9	Institute for Plasma Physics Rijnhuizen

Tungsten damage under simultaneous
steady-state and transient loading
G. De Temmerman1, B. Hensen1, K. Bystrov1, L. Marot2, H.J.
van der Meiden1, J.J. Zielinski1
1Dutch Institute For Fundamental Energy Research (formerly FOM Institute for Plasma Physics

Rijnhuizen), Ass. EURATOM-FOM, Trilateral Euregio Cluster, Postbus 1207, 3430 BE Nieuwegein,The Netherlands
2Dept of Physics, University of Basel, Klingelbergstrasse 82, Basel, SwitzerlandMotivation (2/2)
q Some hints of synergistic effects already observed in NAGDIS/PISCESNAGDIS/ He plasma

PISCES-A/ D plasma

1.4

Laser + Plasma
Laser Only
Plasma Only

1.2

Mass Loss (mg)

13000 Transients withAbsorbed Energy Impact~45 MJ/m2 s1/2

0.8
0.6
0.4

F~ 1026 D+/m2
Tsurf ~ 50ºC

0.200306090Ion Energy [eV] (Vbias-Vplasma)q Need to investigate what happens at higher flux densitiesq An ELM is accompanied by significant ion flux (not included in thoseexperiments)[2] S. Kajita et al, Appl. Phys. Lett. 91 (2007), [3] K. Umstadter et al, Phys. Scr. T138 (2009)
G. De Temmerman

16th ITPA SOL/Div meeting, Juelich, January 2012

120150Experimental procedureq High speed IR camera (25kHz) to minitor surface temperature

Peak surface temperature
800

Temperature (C)

2500

600

2000
1500

400

1000
500

200

B field

00.0

0.5

1.0

1.5

2.0

2.5

3.00

2000
Temperature max (C)Temperature
Heat flux

Heat flux (MW.m-2)

3000

Hydrogen-2
0.3MJ.m

1600
1200
800
400

1.602

Time (s)1.604
1.606Time(s)

1.608

1.610

Temperature risetime: 0.5-1ms relevant for Type-I ELM
Superimposition of divertor relevant steady-state plasma and transient heat/particle pulse
G. De Temmerman

16th ITPA SOL/Div meeting, Juelich, January 2012

Plasma-enhanced surface damage
10x 0.07MJ.m-2

q Measured ablation threshold much lower than
expected

10x 0.15MJ.m-2

10x 0.5MJ.m-2

WI intensity (a.u.)

0.16

1.6T, 10 Pa

0.12

H2He600C
1000C

0.08
0.04
0.00
0.0

10x 0.5MJ.m-2
0.2
0.4
0.60.81.0-2
Energy density to the target (MJ.m )Plasma enhanced surface ablation
G. De Temmerman et al, IAEA FEC, 2010
G. De Temmerman

16th ITPA SOL/Div meeting, Juelich, January 2012

Plasma-enhanced surface damage
10x 0.07MJ.m-2

q Synergistic effect:q Bubble formation due to high-flux plasmaq Explosive release of material during transient

Transient$hea,ng$

10x 0.15MJ.m-2

Transient$hea,ng$Gas,$metal$par,cles,$radicals$

10x 0.5MJ.m-2

Gas$
Metal$

10x 0.5MJ.m-2

Gas$

Re-definition of tolerable energy densitites in
ITER might be necessary
G. De Temmerman et al, IAEA FEC, 2010

G. De Temmerman

16th ITPA SOL/Div meeting, Juelich, January 2012