Impact of ICRF on impurity production in TEXTOR
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ITPA-9, Avila, Spain, 7-1 0. 01. 2008 Impact of ICRF on impurity production in TEXTOR Presented by Marek Rubel Alfvén Laboratory, Royal Institute of Technology, Association EURATOM – VR, Stockholm, Sweden in co-operation with B. Emmoth, P. Wienhold, Ph. Mertens, V. Philipps E. Fortuna, M. Pisarek and W. Zieliński line: Collector probe data Analysis of deposits from ICRF antenna grill
description
Impact of ICRF on impurity production in TEXTOR. Presented by M arek Rubel. Alfv é n Laboratory, Royal Institute of Technology, Association EURATOM – VR, Stockholm, Sweden. in co-operation with B. Emmoth, P. Wienhold, Ph. Mertens, V. Philipps E. Fortuna, M. Pisarek and W. Zieli ń ski. - PowerPoint PPT Presentation
Transcript of Impact of ICRF on impurity production in TEXTOR
ITPA-9, Avila, Spain, 7-10. 01. 2008
Impact of ICRF on impurity production in TEXTOR
Presented by Marek Rubel
Alfvén Laboratory, Royal Institute of Technology, Association EURATOM – VR, Stockholm, Sweden
in co-operation with
B. Emmoth, P. Wienhold, Ph. Mertens, V. Philipps
E. Fortuna, M. Pisarek and W. Zieliński
Outline:
• Collector probe data
• Analysis of deposits from ICRF antenna grill
Impact of ICRF on impurity production Collector probe data (1)
Probe exposure in time-resolved mode to ICRF heated pulses.• Time resolution: 125 ms• Probe position: 25 – 85 mm in the SOL; data presented for 37 mm.
Message:
• Increase of metal (Ni, Cr, Fe) impurity fluxes during ICRF heated pulses.
• Increased deposition rates are measured also for deuterium and oxygen.
Metal Deposition Rates
0
0,2
0,4
0,6
0,8
1
1,2
0 2 4 6 8
Discharge Time [s]
De
po
sit
ion
ra
te [
10
e1
4 c
m-2
s-1
]
INCONEL METALS
ICRF ICRF
Single discharge
Two discharges
00 2 42
Plasma current and density
Impact of ICRF on impurity production Collector probe data (2)
Probe exposure in time-resolved mode to ICRF heated pulses
Message:Increase of metal (Ni, Cr, Fe) impurity fluxes during ICRF heated pulses.
Metal Deposition Rates
0
0,2
0,4
0,6
0 1 2 3 4
Discharge Time [s]
Dep
osi
tio
n R
ate
[10e
14 c
m-2
s-1
]
23756-7
ICRF
Two discharges
1.8 3.4 5.0
ICRH, An-1
5.1 4.6 12.8
4.3 1.1 8.8
ICRH, An-2
5.1 6.9 13.0
Heating Si1015 cm-2s-1
B1014 cm-2s-1
Me1013 cm-2s-1
Impact of ICRF on impurity production Collector probe data (3)
Probe exposure in time-integrated mode to Ohmic and ICRF pulses
Message:Increase of all impurity fluxes during ICRF heated pulses.
Co-deposits on ALT-II and antenna grill
1. ALT-II 2. ICRF antenna
Antenna grill
2m
2m
Deposition zone on ALT-II
ElementElement Limiter Limiter ALT-IIALT-II AntennaAntenna Grill Grill
C 75-80 24-27
O 10-15 15-17
Fe ~1 20-23
Si 1-10 23-28
B 3-10 -
Cr - 6-7
D* 9-12 3-5
Composition of co-deposits:Deposition zone on limiter and antenna grill
Messages:
Differences in the content of elements
• More light elements – C and B - on ALT-II toroidal belt limiter
• Prevalence of heavy elements on the antenna grill
Distribution of elements in co-deposits on the toroidal belt limiter
Message:Heavier elements embedded in an uniform carbon matrix.
C
Fe
Si
Distribution of elements in co-deposits from the antenna grill
Message:Distinct separation of elements in co-deposits from the antenna.
• Increase of impurity fluxes in the SOL during ICRF phase.
• ICRF-induced modification of the SOL (edge temperature, electric sheath, ion trajectories) influence the structure and composition of co-deposits.
• The increase of deuterium atomic density (1.5-3 times) and ion energies (up to 5 times) cause preferential removal of carbon from co-deposits on the antenna.
Concluding Remarks
