MARS-Q modeling of low-n resistive kink-peeling modes and edge harmonic oscillations in DIII-D

Journal Article · Mon Feb 23 00:00:00 EST 2026 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/ae45bc· OSTI ID:3021442

Liu, Yueqiang ^[1]; Chen, Xi ^[1]; Li, Zeyu ^[1]; Ebrahimi, Fatima ^[2]

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1. General Atomics, San Diego, CA (United States)
2. Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Linear and quasilinear magnetohydrodynamic (MHD) modeling is carried out for two DIII-D discharges that both featured a transition from quiescent H-mode (QH) to wide-pedestal QH (WPQH). The MHD perturbations, associated with the edge harmonic oscillations (EHOs) observed during the QH-phase in both discharges, are identified as low-n (n is the toroidal mode number) resistive kink-peeling instabilities, with the ideal MHD counterpart remaining stable. The quasilinear model successfully simulates EHO-like perturbations during the QH phase in both discharges, confirming the experimental observations. A less intuitive finding is the EHO-like behavior involving the n = 2 perturbation, simulated for one of the discharges during the WPQH-phase. This result, while consistent with experimental observations, is obtained despite the fact that the initial perturbation is linearly stable. The eventual growth of the perturbation is solely due to nonlinear interaction between the MHD perturbation and the plasma toroidal flow. The occurrence of the EHO-like perturbation during the WPQH-phase is found to be sensitive to the initial profile of the plasma edge rotation. For DIII-D plasmas considered, the neoclassical toroidal viscosity, generated by three-dimensional low-n perturbations, is found to play a dominant role in modifying the edge flow during EHOs.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: US DOE Office of Science (SC) Fusion Energy Sciences(FES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC02-09CH11466; FC02-04ER54698
• OSTI ID: 3021442
• Journal Information: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 3 Vol. 66; ISSN 1741-4326; ISSN 0029-5515
• Publisher: IOP Science - IAEA
• Country of Publication: United States
• Language: English

Related Subjects

EHO
MARS-F/Q
kink-peeling mode