Abstract Details
Abstracts
Author: Don Spong
Requested Type: Poster
Submitted: 2024-04-12 11:18:53
Co-authors: Y. Ghai, J. Varela, L. Garcia
Contact Info:
Oak Ridge National Laboratory
1 Bethel Valley Road
Oak Ridge, Tennessee 37830
U.S.A.
Abstract Text:
The nonlinear stability characteristics and Alfvén instability driven transport are analyzed for an ITER steady-state case using the FAR3d gyro-Landau closure model. Significant levels of alpha and neutral beam ion transport are observed, at least for the duration of the simulations. This leads to localized flattening in the fast ion profiles. The Alfvén instabilities also drive zonal flow shearing and zonal currents, which could play a role in setting transport barriers for the thermal plasma. The global multiple mode feature of these simulations provides detailed 2D images of the unstable modes and zonal flow structures. The energetic particle transport driven by the Alfvén instabilities is a collective effect related to the phase relations between the fluctuating fast ion density and the fluctuating E x B and magnetic perturbations. This transport is also nonlocal, with finite particle fluxes persisting in regions where the density gradients are zero. This nonlocal feature will require the use of different models to represent the flux/gradient relations in integrated simulations than the often used local, diffusive Fick’s law relation. Understanding and minimizing alpha particle transport in the DT operation of ITER is an important goal of the ITER project; the maintenance of alpha confinement in reversed shear regimes is critical to demonstrate the success of steady-state tokamak operation.
Acknowledgements - This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, under Award DE-AC05-00OR22725.
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