Description
In fusion plasma devices, instabilities such as the Edge Localised Modes (ELMs) can lead to enhanced transport of fast particles and produce damage on the first wall [1,2]. The use of Resonant Magnetic Perturbations (RMPs) can suppress these instabilities [3], but can also lead to substantial fast-ion losses that threaten the integrity of plasma-facing components [4].
In this work, fast-ion modelling has been performed using the ASCOT code [5] for JT-60SA. The simulations accounted for the toroidal field ripple and the effects of Error Field Correction Coils generating RMPs with an n = 3 configuration [6]. The MARS-F code [7] has been used to include the plasma response to the perturbations. The analysis of JT-60SA is of particular interest due to its large fast-ion population, driven by a heating system comprising 14 NBI units with a total power of 34 MW, including two negative NBI units with an injection energy up to 500 keV, setting an ideal environment to study the conditions in future fusion power plants.
These simulations quantified fast-ion losses on the first wall induced by 3D magnetic fields and RMPs, revealing hot spots on plasma-facing components. To characterise the distribution of the lost fast-ion population, synthetic signals of the Fast Ion Loss Detector (FILD) [8] have been calculated using the FILDSIM code [9] for various radial positions, enabling the identification of the NBI units contributing most significantly to the fast-ion losses.
References
[1] T. Eich et al 2005. Journal of Nuclear Materials, 337-339, 669-676
[2] R. Perillo et al 2023 Nucl. Fusion 63 086031
[3] W. Suttrop et al., Phys. Rev. Lett. 106, 225004 (2011)
[4] L. Sanchis et al 2021 Nucl. Fusion 61 046006
[5] E. Hirvijoki et al 2014 Computer Physics Communications 185 1310-1321
[6] M. Honda et al 2018 Nucl. Fusion 58 112012
[7] Y. Liu et al 2016 Plasma Phys. Control. Fusion 58(11) 114005
[8] J. Ayllon-Guerola et al 2021 Fusion Engineering and Design, 167, 112304
[9] J. Galdón-Quiroga et al 2018 Plasma Phys. Control. Fusion 60 105005