Abstract Details
Abstracts
Author: Gregory W Hammett
Requested Type: Poster
Submitted: 2025-03-15 11:40:38
Co-authors: Noah R. Mandell, Tess Bernard, Manaure Francisquez, Ammar Hakim, Antoine Hoffmann, James L. Juno, Akash Shukla
Contact Info:
Princeton Plasma Physics Laboratory
100 Stellarator Drive
Princeton, NJ 08540
USA
Abstract Text:
A plasma sheath has a current versus potential relationship that leads to an effective resistivity, which can help drive instabilities in the SOL Scrape-Off Layer of tokamaks. We discuss the conducting sheath model in the Gkeyll [1] edge gyrokinetic turbulence code and carry out a linear stability analysis of bad-curvature-driven drift-ballooning instabilities in the SOL to look at the effects of this sheath resistance. At long wavelengths, the model approaches the ideal MHD limit, where the magnetic field in the SOL is frozen into the divertor plates. This line tying is strongly stabilizing (as known from other studies). But at shorter wavelengths with FLR effects, the sheath resistance becomes important and allows the foot points of the field lines to slip relative to the divertor plates, leading to interchange-like dynamics. We give a brief status report on the development of capabilities in Gkeyll, show examples of 3D edge turbulence simulations including closed and open field line regions simultaneously in limited plasmas, including for negative triangularity (NT) plasmas in the DIII-D [2] and TCV tokamaks. Gkeyll can also be run in an axisymmetric 2D limit with a model for radial transport, as a kind of gyrokinetic analogue of divertor modelling codes like SOLPS, but including kinetic effects like trapped particles. These kinetic effects can significantly reduce the penetration of impurities from the divertor to the midplane [3].
[1] https://gkeyll.readthedocs.io/
[2] T N Bernard, F D Halpern, M Francisquez, et al., PPCF 2024, https://doi.org/10.1088/1361-6587/ad8186
[3] A. Shukla, J. Roeltgen,1, M. Kotschenreuther, et al., subm. to Phys. Plasmas, see also https://meetings.aps.org/Meeting/DPP24/Session/GI03.4
Acknowledgements: Supported by the DOE Office of Fusion Energy Sciences, the CEDA SciDAC project, a DOE Distinguished Scientist award, and others via DOE Contract Number DE-AC02-09CH11466 for the Princeton Plasma Physics Laboratory.
Characterization: 4.0
Comments:
Place next to the poster by Dingyun Liu, in the order: [1] Hammett, [2] Liu.