April 4-6

Abstract Details

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Author: Hongxuan Zhu
Requested Type: Consider for Invited
Submitted: 2022-03-09 10:40:05

Co-authors: T. Stoltzfus-Dueck, R. Hager, S. Ku, and C. S. Chang

Contact Info:
Princeton Plasma Physics Laboratory
100 Stellarator Road
Princeton, NJ   08540

Abstract Text:
Ion-orbit loss is considered important to the radial electric fields Er of tokamak edge plasmas. In neoclassical equilibria, collisions can scatter ions onto the loss orbits and generate a steady-state radial current, which may drive the edge Er away from the confined-region neoclassical value without orbit-loss. To quantitatively measure this effect, an ion-orbit-flux diagnostic [1,2] has been implemented in the axisymmetric version of the gyrokinetic particle-in-cell code XGC [3,4]. The validity of the diagnostic is demonstrated by studying the collisional relaxation of Er in the core plasmas. Then, the ion orbit-loss effect is numerically measured in the edge plasmas in the DIII-D geometry. It is found that the effect of the collisional ion orbit loss is more significant for an L-mode plasma compared to an H-mode plasma.

[1] T. Stoltzfus-Dueck, Nucl. Fusion 60, 016031 (2020).
[2] T. Stoltzfus-Dueck and H. Zhu, Plasma Phys. Control. Fusion 63, 115001 (2021).
[3] See https://www.osti.gov/doecode/biblio/12570 for more details about the code XGC.
[4] H. Zhu, T. Stoltzfus-Dueck, R. Hager, S. Ku, and C. Chang, to appear in Nucl. Fusion.