Contrib. Plasma Phys. zyxwvu MLKJIH 38 (1998) 1/2, 20-25 2D Modelling of the Edge Plasma in ITER A.S. Kukushkin, H.D. Pacher', D. Costert, G. Janeschitz, D. Reiter*, R. Schneidert zyxwvut GFEDCBA ITER Joint Central Team, Garching Joint Worksite, Garching. Germany zyxw * zyxwvuts EDCBA The NET Team, Garching. Germany; t Max-Planck IPP. Garching, Germany; t FZ Jiilich, Jiilich. Germany 1. Introduction The divertor is one of the most challenging parts of the ITER design [I]. It must withstand severe power loads of about 10 MW/m2 during 3000 pulses before replacement, ensuring also proper conditions for helium removal. Compatibility with the core plasma imposes additional constraints which should be met - with respect to the input power, the plasma density upstream, and the Zeff at the core-edge interface (CEI). The ITER approach to the solution of this problem is to optimise the divertor radiation using some impurity seeding and to work with detached (or partially attached) plasma [2,3]. The present paper contains initial results of the numerical investigation of the possible operational space of the ITER divertor. 2. Modelling setup The B2-Eirene code package [4,5] has been used in the calculations. It employs full multi-fluid treatment of impurities together with a Monte-Carlo model for neutrals. The plasma is composed of D. He, C, and Ne ions and neutrals. The hydrogen density is specified to be constant, zyxwvut GFEDCBA n,, at the CEI. Additional gas puffing at a rate of 1022s-I together with pumping from the private flux region (PFR) is also included in the model. The intrinsic helium concentration is set to 10% at the CEI as the boundary condition. Carbon is assumed to be sputtered, with zero net flux across the CEI (steady state). Realistic physical sputtering is included and a simplified model is used for chemical sputtering: carbon atoms with 1 eV energy are sputtered rather than hydrocarbon molecules at a constant sputtering yield Ych. Seeded neon is introduced through its concentration at the CEI in the same way as helium. The cross-field diffusivities have been assumed to be constant. The input power is set at zy M 200 zyxwvutsr GFEDCBA MW presupposing -100 M W radiation from the core [ll. Exploration of the operational space is done in terms of the neon seeding level, the upstream plasma density, the cross-field transport, the chemical sputtering yield, the carbon covered area, and the "dome" shape, Given the high dimensionality, no regular coverage of the operational space could be provided, and 1D and 2D parameter scans were done instead.