TRANSP SIMULATIONS OF INTERNATIONAL THERMONUCLEAR EXPERIMENTAL REACTOR PLASMAS

The TRANSP code [R. V. Budny et al., Nucl. Fusion 35, 1497 (1995)] is used to construct comprehensive, self-consistent models for plasmas wi thin the separatrix surface in the International Thermonuclear Experim ental Reactor (ITER) [Technical Basis for the ITER Interim Design Repo rt, Cost Review and Safety Analysis (International Atomic Energy Agenc y, Vienna, 1996)]. Steady state profiles of two plasmas from the ITER ''Interim Design'' database are used. Effects of 1 MeV neutral beam in jection, sawteeth mixing, toroidal field ripple, and helium ash transp ort are included. Results are given for the fusion rate profiles, and parameters describing effects such as the alpha particle heating of el ectrons and thermal ions, and the thermalization rates. The modeling i ndicates that the deposition of the neutral beam ions will peak in the plasma center, and the average beam ion energy will be half the injec ted energy. Sawtooth mixing will broaden the fast alpha profile. The t oroidal ripple loss rate of alpha energy will be 3% before sawtooth cr ashes and will increase by a factor of 3 immediately following sawtoot h crashes. Various assumptions for the thermal He transport and the He recycling coefficient at the separatrix R(rec) are used. If the ratio of helium and energy confinement times, tau(He)/tau(E) is less than 15, the steady state fusion power is predicted to be 1.5 GW or greater . The Values of the transport coefficients required for this fusion po wer depend on R(rec). If this is larger than about 0.5, and if the inw ard pinch is small the required He diffusivity must be much larger tha n that measured in tokamaks. (C) 1996 American Institute of Physics.