7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

Linear and quasi-linear toroidal modelling of resonant magnetic perturbations inpreparation for eight ITER H-mode scenarios
L. Li1, Y. Q. Liu2, A. Loarte3, S. D. Pinches3, A. Polevoi3, M. Becoulet4, G. T. A. Huijsmans4, and F.
C. Zhong1
1
College of Science, Donghua University, China, 2 General Atomics, USA, 3 ITER Organization,France,4CEA, France
e-mail (speaker): lili8068@dhu.edu.cn
Large scale (type-I) edge localized modes (ELMs) are ofsignificant concern in future devices such as ITER [1],since large amount of particles and heat fluxes can bereleased onto the plasma facing components during each
ELM bursts. Fortunately, the resonant magnetic
perturbation (RMP) has been shown experimentally to becapable of successfully controlling type-I ELMs in many
present-day tokamak devices [2-9]. Extensive theoreticaland modelling efforts have helped establish that theplasma response plays an important role in understanding
the ELM mitigation/suppression physics.
This work aims at a systematic numerical study of bothlinear and quasi-linear plasma response to RMP fields foreight H-mode scenarios designed for ITER with varying
plasma current and magnetic field [10], utilizing thetoroidal resistive MHD codes MARS-F [11] and MARSQ [12].
Based on the MARS-F computed linear response, thesurface displacement near the X-point of the divertor
plasma is used as a criterion to optimize the RMP
configuration for ELM control. The results reveal that theoptimal RMP coil current phasing for controlling the typeI ELMs scales roughly linearly with the edge safety factor
q95. Certain deviation from this scaling also occurs (for theITER 7.5 MA/4.5 T and 7.5 MA/5.3 T scenarios) due tovariation of the vacuum RMP field spectrum at higher q95value (but not directly due to the plasma response).
Quasi-linear initial-value simulation of the plasma
response has also been carried out, focusing on the n=3
RMP coil configuration for ITER. Here, the study aims at
minimizing the side effects of RMP on the plasma
momentum and particle confinement for the ITER

scenarios. For several scenarios (such as the 15 MAbaseline scenario), the RMP induced change of the plasmaedge flow is found to be un-voidable. Similar effects dueto RMP are also found on the plasma density. In general,
RMP with the optimal coil phasing (for ELM control)
provides the strongest particle transport. For ITER, thisside effect can be large and sensitive to choice of theplasma scenario, as well as to the coil current phasing.
The plasma response based on the linear and quasilinear models provides useful guidance to the choice of
the ELM control coil configurations in ITER. It should
however be realized that other physics, e.g. fully nonlinear MHD, also play important roles in understanding
ELM control in particular the ELM suppression.
This work is supported by National Natural Science
Foundation of China (NSFC) [grant numbers 12075053]
and by National Key R&D Program of China undercontract No. 2022YFE03060002.
References[1] Loarte A et al 2014 Nucl. Fusion 54 033007[2] Evans T. et al 2004 Phys. Rev. Lett. 92 235003[3] Liang Y. et al 2007 Phys. Rev. Lett. 98 265004[4] Hawryluk R.J. et al 2009 Nucl. Fusion 49 065012[5] Nardon E. et al 2009 Plasma Phys. Control. Fusion
51 124010[6] Kirk A. et al 2010 Nucl. Fusion 50 034008[7] Suttrop W. et al 2011 Phys. Rev. Lett. 106 225004[8] Jeon Y.M. et al 2012 Phys. Rev. Lett. 109 035004[9] Sun Y. et al 2016 Phys. Rev. Lett. 117 115001[10] Li L. et al 2022 Nucl. Fusion 62 096008[11] Liu Y. Q. et al 2000 Phys. Plasmas 7 3681
[12] Liu Y. Q. et al 2013 Phys. Plasmas 20 042503

Figure 1. The optimal coil phasing for eight ITER scenarios computed by the linear plasma response (left) for the threerow (U+M+L) ELM control coil configuration. MARS-Q simulated time traces for the net change of the toroidal rotation
frequency at the magnetic axis (middle) the plasma density (right) integrated over the plasma volume for the 15 MA/5.3
T/Q=5 ITER scenario at 90 kAt coil current. where, the n=3 RMP coil configuration is assumed.