1. 1ITPA meeting IOS, Oct 2011Arne Kallenbach IOS-1.2 Study seeding effects on ITER demo discharges (Oct 2011) - closely related to IOS-1.1, development of ITER demonstration discharges Strategy: Ideally, ITER demonstration discharges should be developed with integrated impurity seeding. Due to technical constraints and difficulties, seeded scenarios and ITER demonstration discharges (IOS-1.1) are developed in parallel, to be combined in the future. The combination of low q 95, and high  is in particular challenging for high-Z devices. Sufficient central heating and ELM control are essential. Physics Studies:  Multi-machine similarity discharges with identity params  *, n/nGreen and P/R (2010 /2011) B=const, I p ~R, validate radiative efficiency data and scalings  dZ eff in ITER  Combine radiative seeding with ELM control (RMPs, pellets, …) Status/plans: Seeding results (AUG, JET, C-mod, DIII-D) reported on PSI 2010 (JNM online/in press) Wait for new seeding results from JET with ILW, then close IOS-1.2 (possibly define follow-up JE) Final report foreseen for autumn 2012 Focus of experiments and analysis in remaining time: 1) seeding in ITER-shaped plasmas (JET, C-Mod, AUG) 2) identify the best sensor signal for feedback control in ITER Contributors: A. Kallenbach (Spokes person, AUG), T. Petrie (DIII-D), G. Maddison (JET), M. Reinke/S. Wolfe (C-Mod), V. Soukhanovskii (NSTX)

2. 2ITPA meeting IOS, Oct 2011Arne Kallenbach ASDEX Upgrade: High power seeding with peak heatload < 5 MW/m 2 Peak load < 5 MW/m 2 ! Combined strong D divertor puff, feedback controlled N divertor seeding (q 95 =3.7,  u =0.1,  l =0.43) Modelling with B2-Eirene about to start

3. 3ITPA meeting IOS, Oct 2011Arne Kallenbach  (3 points with outward-shifted OSP removed)  Unseeded pulses with OSP sweeping at 4 Hz show drop in outboard-target inter-ELM heat load (and  Z eff  t ).  Adding N seeding under RTC (using inboard- divertor filtered NVA as sensor) reduces inter-ELM heat load further while maintaining  H 98y  t & lower  Z eff  t  greater effect per extrinsic ion.  Similar inter-ELM exhaust moderation in swept, RTC case for only  40% of N input in unswept, feedforward counterpart. References from feedforward N series v. inter-ELM radiance of 20.93 nm line (NVA) show shot-to-shot legacy (in all-C machine). OSP sweeping + RTC seeding in JET Type I H-mode Optimum sensor for heatflux feedback control not yet clear JET uses NV emission line (20.93 nm) so far