April 15-17

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Abstracts

Author: Jeff B. Parker
Requested Type: Poster
Submitted: 2019-02-24 20:50:21

Co-authors: L. L. LoDestro, G. Merlo, D. Told, F. Jenko, L. Ricketson, A. Campos, J. Hittinger

Contact Info:
Lawrence Livermore National Laboratory
7000 East Ave, Lawrence Liverm
Livermore, CA   94550
United States

Abstract Text:
Whole-device modeling and quantitative predictive capability will require innovative algorithms to faithfully simulate the multi-scale nature of fusion plasma. The dynamical evolution of macroscopic plasma profiles such as temperature and density can occur on timescales as long as seconds, while the microturbulence responsible has an inherent timescale on the order of microseconds. In standard orderings for a tokamak core, turbulence and transport dynamics can be rigorously separated through a multiscale asymptotic expansion. Conventional modeling involves reduced models for predicting turbulent fluxes, such as quasilinear models. Here, we describe our progress in coupling transport directly with massively parallel gyrokinetic turbulence simulations. We have written a transport code Tango that implements a unique algorithm designed for coupling with turbulence. Tango has been coupled to the global gyrokinetic GENE. Our previously reported numerical results included successfully finding the steady-state temperature profile in response to turbulence simulations that used adiabatic electrons. Here, we report on encouraging progress in coupling transport with turbulence simulations that involve kinetic electrons, and the simultaneous evolution of ion temperature, electron temperature, and density. We describe how the numerical coupling method is generalized for this situation, and we remark on how the multi-channel transport nature is more challenging.

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