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Author: Nathan T Howard
Requested Type: Poster
Submitted: 2017-03-19 21:36:04

Co-authors: C. Holland, A.E. White, M. Greenwald, J. Candy, A.J. Creely

Contact Info:
MIT - PSFC
175 Albany St.
Cambridge, MA   02139
USA

Abstract Text:
Cutting-edge simulations that simultaneously capture both ion and electron-scale turbulence have been performed for ITER-like conditions in Alcator C-Mod. Operated with ITER-like toroidal field, density, and coupled ions and electrons (Ti~Te), these conditions help shed light on the possible influence of cross-scale coupling in predictions of ITER. Using the GYRO code, multi-scale simulations utilized all experimental inputs (kinetic profiles and geometry) and realistic electron mass (mi/me = 3600) to capture the dynamics of electromagnetic (delta phi & delta A_||) turbulence with k_theta rho_s up to 42.0 while including e-i & i-i collisions, 3 gyrokinetic species and ExB shear effects. In qualitative agreement with previous investigations in L-mode, this work demonstrates that cross-scale coupling can significantly affect the saturation of the turbulence at ion-scales, resulting in enhanced levels of heat transport. It is demonstrated that experimental ion and electron heat fluxes can be simultaneously reproduced with multi-scale simulation but unlike L-mode conditions, high-k TEM/ETG turbulence does not appear to play the dominant role in reproducing measured electron incremental diffusivities. Quantitative comparisons with experiment, the origin of the measured incremental diffusivities, and the implications of cross-scale coupling for prediction of ITER will be presented. Supported by US DOE grant DEFC02-99ER54512-CMOD.

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