Investigation of multi-mode plasma response in EAST and its application in ITER scenario*

The multi-mode plasma response provides an effective way to extract the pressure-driving and current-driving modes. Recent RMP-ELM control studies found that the multi-mode plasma response offers another way to understand the plasma shaping effects on ELM control. To understand the physics of such technique, the 3D plasma response is investigated systematically in EAST by varying the plasma pressure and current, whilst keeping other equilibrium quantities largely unchanged. It reveals that one mode has strong correlation with the plasma pressure, while the other mode dependences on the plasma current. This indicates the multi-mode plasma response analysis can extract the pressure-driving and current-driving modes. Furthermore, such technique is applied to the ITER case, which shows a third-mode that has the feature in between. These findings indicate that the multi-mode plasma response is an effective technique for 3D MHD analysis, and that predictive plasma response calculation can be used to maximize access to RMP-ELM control in future devices.