5 research outputs found
Non-linear MHD modelling of Edge Localized Modes suppression by Resonant Magnetic Perturbations in ITER
International audienceEdge Localized Modes (ELMs) suppression by Resonant Magnetic Perturbations (RMPs) was studied with non-linear resistive MHD code JOREK for ITER H-mode scenarios 15MA,12.5MA,10MA/5.3T, obtained by the ASTRA code. • RMP spectra, optimized by the linear MHD MARS-F code, with main toroidal harmonics N=2, N=3, N=4 used as boundary conditions of the computational domain of JOREK including realistic RMP coils, plasma, divertor and wall geometry. The model includes all relevant plasma flows: toroidal rotation, two fluid diamagnetic effects and neoclassical poloidal friction. • The threshold for ELM suppression was found at a maximum RMP coils current of 45kAt-60kAt compared to the coils maximum capability of 90kAt. With RMPs, the main harmonic and the non-linearly coupled harmonics remain dominant at the plasma edge, producing continuous MHD turbulent transport and suppressing ELMs in all scenarios. • In the high beta poloidal steady-state 10MA/5.3T scenario a rotating QH-mode without ELMs was observed even without RMPs. N=3 RMPs induced a static QH-like mode, locked to the RMP fields in this scenario. • The 3D divertor heat and particle fluxes in the stationary RMP phase show the characteristic splitting with the main RMP toroidal symmetry. The radial extension of the footprints typically was ~20 cm in inner divertor and ~40 cm in outer divertor with heat fluxes decreasing further out from the initial strike point from ~6-5MW/m 2 to ~1MW/m 2 in the stationary regime with RMPs and total power in the divertor ~50MW. The footprints remain within the divertor target and baffle areas. However in transient regimes when RMPs are switched on, part of plasma thermal energy is lost and these heat fluxes can be much larger; optimization of RMP switch-on needs to be studied further with respect to the ensuing power fluxes and L-H access