Investigation of 3D perturbation fields in TCABR, ITER, and DIII-D tokamaks.

3D perturbation fields are widely used for suppressing Edge Localized modes (ELMs) in H-mode tokamak discharges. DIII-D can apply n=1,2 and 3 magnetic perturbations using the existing I- and C-coil sets and up to n=6 using the planned M-coils. ITER's design includes three rows of 9 coils each and will use n=3 and n=4 fields for ELM suppression. The upgraded TCABR tokamak (R0 = 0.62 m, a = 0.2 m, B0 ≤ 1.1T, IP ≤ 100 kA, max. discharge duration of 100 ms) operated at the University of Sao Paulo, Brazil, will have 3 rows of 18 internal coils located on the Low Field side and 3 rows of 18 coils each situated on the center post. In this work, we study the effects on the edge plasma magnetic topology and the magnetic footprints on the divertor surfaces produced by the proposed TCA-BR non-axisymmetric coil sets using TRIP3D-SURFMN and M3D-C1 plasma response codes. The results from the application of low (n=3) and high (n>3) toroidal mode number perturbation fields from the TCA-BR coils are compared to the existing and proposed DIII-D coil sets as well as to the ITER ELM coils using a set of previously developed metrics.