Abstract Details
Abstracts
Author: Robert Hager
Requested Type: Poster
Submitted: 2024-04-11 21:06:47
Co-authors: T. Gade, B. Sturdevant, S. Ku, A. Mishchenko, C.S. Chang
Contact Info:
Princeton Plasma Physics Laboratory
100 Stellarator Road
Princeton, New Jersey 08540
USA
Abstract Text:
For improved accuracy of MHD-type modes, a toroidally spectral field solver has been implemented and verified in the global electromagnetic total-f gyrokinetic code XGC. The new field solver drops the approximation that the poloidal magnetic field is small compared to the toroidal field. Instead, the full gradient perpendicular to the magnetic field is used in the gyrokinetic Poisson equation and Ampére’s law. This improvement is crucial for accurate simulation of electromagnetic modes with low-toroidal mode number (low-n, MHD-type), especially at low to moderate aspect ratio. The need for the improved field solver for low-n modes is verified in a detailed study of the difference between the solutions of XGC’s usual and the toroidally spectral solver. For high-n modes, we find that difference to be small. The accuracy of the new field solver is verified for several MHD-type modes, e.g. Alfvén waves, internal kink, and peeling-ballooning modes. To achieve high accuracy and performance in simulations including toroidal mode numbers from the MHD to the microturbulence range, XGC’s usual and toroidally spectral solvers are used alongside each other for high-n and low-n, respectively.
This material is based upon work performed at Princeton Plasma Physics Laboratory under contract DE-AC02-09CH11466 and supported by i) the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research and Office of Fusion Energy Science, Scientific Discovery through Advanced Computing (SciDAC) program, and ii) the U.S. Department of Energy Computational Science Graduate Fellowship under Award Number(s) DE-SC0023112. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a Department of Energy Office of Science User Facility using NERSC awards ERCAP0027958/ERCAP0027464.
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