Integrated modeling of steady-state scenarios for ITER; Physics and computational challenges

Giruzzi, G.*; Park, J. M.*; Murakami, M.*; Kessel, C. E.*; Polevoi, A.*; Sips, A. C. C.*; Artaud, J. F.*; Basiuk, V.*; Bonoli, P.*; Budny, R. V.*; Fukuyama, Atsushi*; Garcia, J.*; Hayashi, Nobuhiko; Honda, Mitsuru; Ide, Shunsuke; Imbeaux, F.*; Joffrin, E.*; Luce, T.*; Na, Y.-S.*; Oikawa, Toshihiro; Ozeki, Takahisa; Prater, R.*; Schneider, M.*; St.John, H.*; Tuccillo, A. A.*; ITPA/Steady-State Operation Groups*

The modeling of the steady-state ITER scenarios is reviewed, as a subject of common work of the ITPA-SSO group. Focus is made not only on the basic physics issues, resulting from theory and experiments, but also on the difficulties and the needs of integrated modeling. Specific issues connected with high bootstrap fraction in the long pulse operation are addressed. Bootstrap current can be enhanced either by large pedestal temperatures, or by Internal Transport Barriers (ITB). Recent simulations for both high-pedestal scenarios and ITB scenarios are compared. Results of code benchmarking for typical parameters of ITER scenarios are also analyzed, and prospects for improvement of the integrated modeling capability will be discussed.