Boundary plasma modeling for ITER. Final report, July 1, 1992--December 31, 1994

Under this contract the authors have contributed to ITER edged plasma physics by improving the numerics and the organization of the B2.5 edge plasma code, by applying the code in a systematic study of the effect of deliberately introduced impurities upon the divertor heat load, by collaborating with colleagues at IPP Garching in their studies of the ITER divertor using the B2/EIRENE code system and in their model validation studies, and by kinetic studies of the possible beneficial effects of magnetic perturbations upon divertor heat load. In regard to the effect of recycling impurities their modeling indicates that it will be possible to radiate up to 200 MW in the edge plasma and divertor if the edge density is sufficiently high ({approx_equal} 6.0 {times} 10{sup 19}/m{sup 3}) and if there is maintained a concentration of 1.0% neon or 0.5% argon. This implies that an acceptable working point for ITER may just barely be possible with credit for bremsstrahlung and edge radiation alone, and a robust working point appears possible if consideration is given also to core plasma impurity radiation. In regard to the effect of magnetic perturbations they find that a scenario that relies on external windings requires coils no further than about 0.3 m outside the separatrix, which appears unacceptable given the radiation environment