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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.
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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 ITPA-9, Avila, Spain, 7-10. 01. 2008
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. Plasma current and density 0 2 0 2 4 • Message: • Increase of metal (Ni, Cr, Fe) impurity fluxes during ICRF heated pulses. • Increased deposition rates are measured also for deuterium and oxygen.
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.
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 Deposition zone on ALT-II 2 2mm 1 Antenna grill 1. ALT-II 2. ICRF antenna 2mm
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 Fe C Si Message: Heavier elements embedded in an uniform carbon matrix.
Distribution of elements in co-deposits from the antenna grill Message: Distinct separation of elements in co-deposits from the antenna.
Concluding Remarks • 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.