Description
In ITER, mitigation of Edge-Localized Modes (ELMs) is essential to limit transient heat loads on plasma-facing components and ensure reliable divertor operation. Non-axisymmetric Resonant Magnetic Perturbations (RMPs) are a primary candidate for ELM control. This work investigates the plasma response and edge magnetic topology induced by n=3 RMPs in ITER high edge safety factor (high-q) DT-1 scenarios, with emphasis on toroidal rotation effects and divertor heat flux patterns.
Linear plasma response calculations are performed using MARS-F to evaluate the interaction between RMP coils and the plasma equilibrium under varying plasma current and rotation profiles. The resulting perturbed magnetic fields are traced through the scrape-off layer (SOL) and into the divertor region using FLARE, providing three-dimensional magnetic topology inputs for EMC3-EIRENE simulations. The coupled fluid–Monte Carlo framework is applied assuming pure deuterium plasma to analyse stochastic layer formation, particle transport, and power deposition characteristics.
Coil phasing scans indicate a non-monotonic dependence of the edge response on plasma parameters. In high-q DT-1 equilibria, variations in toroidal rotation produce comparatively modest changes in stochastic layer structure and divertor heat flux modification, suggesting a reduced sensitivity to rotation-driven amplification mechanisms. This behaviour is consistent with altered resonant surface spacing in high-q edge geometries, which affects field-line connection patterns and the effective coupling between applied perturbations and the plasma response.
The high-q configuration also introduces closely spaced resonant magnetic surfaces in the edge region, leading to enhanced field-line complexity and significant challenges in three-dimensional grid generation for transport simulations. Ongoing work addresses these numerical constraints to enable systematic comparison with SRO cases and to quantify differences in divertor power deposition and stochastic layer properties.
Overall, this study provides insight into RMP-induced three-dimensional edge dynamics in ITER high-q DT-1 conditions and supports the development of robust ELM control strategies. Future work will extend the analysis to realistic transport coefficients and multi-species impurity modelling to assess broader implications for divertor performance and plasma–material interaction.