Magnetohydrodynamic-calibrated edge-localized mode model in simulations of International Thermonuclear Experimental Reactor

Abstract

Self-consistent simulations of the International Thermonuclear Experimental Reactor (ITER) [R. Aymar, P. Barabaschi, and Y. Shimomura, Plasma Phys. Controlled Fusion 44, 519 (2002)] have been carried out using the JETTO-integrated modeling code in which theory-motivated models are used for the H-mode pedestal and for the stability conditions that lead to the edge-localized mode (ELM) crashes. Transport is described by combining the anomalous mixed Bohm/gyro-Bohm model [M. Erba, A. Cherubini, V. V. Parail, and A. Taroni, Plasma Phys. Controlled Fusion 39, 261 (1997)] with the NCLASS neoclassical transport model [W. A. Houlberg, K. C. Shaing, S. P. Hirshman, and M. C. Zarnstorff, Phys. Plasmas 4, 3231 (1997)] in the core region, while only neoclassical transport is used in the pedestal region. In the simulations, an ELM crash can be triggered either by a pressure-driven ballooning mode or by a current-driven peeling mode, depending on which instability reaches its stability criterion first. The equilibrium and magnetohydrodynamics (MHD) stability analyses codes, HELENA and MISHKA [A. B. Mikhailovskii, G. T. A. Huysmans, S. E. Sharapov, and W. Kerner, Plasma Phys. Rep. 23, 713 (1997)], are used to evaluate the edge stability of the plasma just prior to an ELM crash in order to calibrate and confirm the validity of the stability criteria used to trigger ELMs in the JETTO simulations. It is found that the simulation of the ITER baseline case yields a fusion Q of 16.6, with the electron and ion temperatures at the top of the pedestal of 4.4 and 4.9keV, respectively. The high values of the pedestal temperature result from access to the second stability region of the ballooning mode. Simulation sensitivity studies are carried out by varying parameters such as the auxiliary heating power and the width of the pedestal. When the auxiliary heating power is turned off, it is found that significant fusion power is sustained and that access to ballooning mode second stability is maintained.