Speaker
Dr
Guido Huijsmans
(ITER Organization)
Description
Validation of MHD models and MHD simulations on current experiments is needed to provide a physics basis for the application of these models to ITER. This paper describes the progress made towards validation in the area of the stability of the H-mode edge pedestal and ELM control.
ELM control: pellet pacing
The injection of pellets is one of the methods foreseen to control ELM energy losses and power fluxes in ITER. Previous non-linear MHD simulations using the JOREK code of pacing pellets in DIII-D have shown that the minimum pellet size for an ELM trigger is correlated with the 3D pressure perturbation created by the pellet. This has been extended to the simulation of pacing pellets injected in JET. The simulation domain including the divertor allows simulation of a full pellet triggered ELM cycle. The simulated ELM size is found to depend on the pedestal properties of the target plasma. The divertor heat load shows a n=1 asymmetry for low field side injection (as observed experimentally). The paper will discuss the dependence of the power deposition asymmetry on the injection geometry and the consequences for ITER.
ELM control: QH-mode
Recently, DIII-D has made significant progress in the development of ELM free QH mode plasmas in an ITER relevant regime, using the RMP coils to control the rotation profile. To develop the physics basis for ITER, non-linear MHD simulations of DIII-D QH-mode plasmas have been performed. The JOREK code has been coupled with the STARWALL code for the resistive wall, vacuum and coils contributions. The influence of the rotation and rotation shear on the stability and saturation of the kink mode will be investigated and compared with DIII-D experiments.
SOL MHD stability
Observations of the SOL heat flux width of the inter-ELM scrape-off layer (SOL) for low density H-modes, show an inverse dependence on the poloidal field. Extrapolating to ITER results in a narrow SOL width of ~ 1 mm. The MHD stability limits of the pedestal and SOL pressure profile have been analysed to evaluate whether MHD limits could prevent such narrow profiles. ITER scenarios with narrow SOL widths are found to be stable to infinite-n ballooning modes. The ballooning stability in the pedestal shows a higher (by ~40%) stability limit in the SOL compared to the pedestal. This indicates that the narrow SOL are consistent with MHD stability limits in ITER.
| Country or International Organisation | ITER Organization |
|---|---|
| Paper Number | TH/6-1Ra |
Primary author
Dr
Guido Huijsmans
(ITER Organization)
Co-authors
Mr
A. M. Garofalo
(General Atomics)
Dr
Alberto Loarte
(ITER Organization)
Dr
Eric Nardon
(CEA)
Dr
Feng Liu
(ITER Organization)
Dr
Florian Koechl
(Association EURATOM-ÖAW/ATI, Atominstitut, TU Wien)
Dr
Mathias Hoelzl
(Max Planck Institute for Plasma Physics, Garching)
Dr
Shimpei Futatani
(Ecole Centrale de Lyon)
