Abstract Details
Abstracts
Author: Joseph R Jepson
Requested Type: Poster
Submitted: 2023-03-31 09:09:15
Co-authors: C. C. Hegna, E. D. Held, J. A. Spencer, E. C. Howell
Contact Info:
University of Wisconsin - Madison
1500 Engineering Dr
Madison, WI 53706
United States
Abstract Text:
In an effort to incorporate kinetic ion physics in extended MHD simulations, a Chapman-Enskog-like (CEL) approach [1] is used in NIMROD simulations. The kinetic aspects of the formulation have been successfully benchmarked against the predictions of neoclassical theory for poloidal ion flows in axisymmetric tokamak geometry [2]. The CEL implementation allows for a rigorous kinetic closure of NIMROD’s fluid model as the kinetic equation is solved for in the presence of a self-consistent background Maxwellian defined by temporally and spatially evolving density, temperature and fluid velocity. Numerical stability considerations of the full coupled fluid-kinetic system are non-trivial, and are discussed herein. We also, for an initial test, model the axisymmetric fluid evolution from an EFIT equilibrium based on DIII-D Iter-Baseline-Scenario (IBS) discharge 174446 at 3390 ms. We initialize an MHD equilibrium in the absence of equilibrium fluid flow profiles. Due to the presence of equilibrium ion temperature gradients, neoclassical physics predicts that self-consistent ion flows will be generated. In this work, the evolution of ion fluid flows is simulated for an initially static axisymmetric equilibrium until a self-consistent equilibrium state with plasma flows is developed. [1] J. J. Ramos, Physics of Plasmas textbf{17}, 082502 (2010). [2] J. R. Jepson, C. C. Hegna, E. D. Held, J. A. Spencer, and B. C. Lyons, Physics of Plasmas textbf{28}, 082503 (2021)
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