Measurement of plasma response to n=2 fields using saddle loops on JET

摘要

Introduction Active control of Type-I edge-localized mode (ELM) using 3D fields has been demonstrated in several tokamaks [1-5], and it provides an attractive method for ELM control in ITER. To date, more and more experimental results show the plasma response to the 3D perturbation fields is important for understanding the mechanism of ELM control. On JET, it has been found that the plasma response to n = 2 fields measured by saddle loops was saturated during the ramp-up of the current flowing in the error field correction coils (EFCCs) [6]. Recently, the experiment in DIII-D shows rapid increase in the inner-wall magnetic response to an n= 2 field when the plasma transitions into ELM suppression [7].